Process for using biogenic carbon dioxide derived from non-fossil organic material

ABSTRACT

The present disclosure provides a process for forming a biogenic carbon-based fuel or a fuel intermediate from biogenic carbon dioxide and hydrogen. The hydrogen is sourced from a process that produces hydrogen and fossil carbon dioxide from a fossil-fuel hydrocarbon and separates the fossil carbon dioxide from the hydrogen. The process may further comprise carrying out or arranging for one or more parties to carry out at least one step that contributes to a reduction in the GHG emissions of the biogenic carbon-based fuel, or a fuel made from the fuel intermediate, of at least 20% relative to a gasoline baseline. In various embodiments this includes (a) introducing the fossil carbon dioxide underground, and/or (b) using a biogenic carbon-based product selected from a chemical and energy product produced from the non-fossil organic material to displace the use or production of a corresponding fossil-based product. Methods of using the present invention to enable fuel credit generation are also described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. provisional application No.62/027,370 filed Jul. 22, 2014, which is incorporated by referenceherein.

TECHNICAL FIELD

The present invention relates to a process for using biogenic carbondioxide derived from non-fossil organic material for producing a fuel orfuel intermediate.

BACKGROUND

The majority of the energy used today is derived from fossil fuels,despite the on-going controversy surrounding their environmental impact.Fossil fuels, as with any carbon-containing materials, release carbondioxide upon their combustion. The extraction of fossil fuels for energyproduction results in the release of carbon into the atmosphere that waspreviously stored in the earth, and thereby has a net effect ofincreasing the levels of atmospheric carbon dioxide. A major source ofatmospheric fossil carbon dioxide comes from “tailpipe emissions” fromcars and carbon dioxide-containing flue gases from fossil fuel burningpower plants.

On the other hand, carbon dioxide released from combusting fuel derivedfrom non-fossil organic material is relatively benign, given that itsimply returns to the atmosphere carbon that was recently fixed byphotosynthesis. More generally, this relatively benign nature is alsotrue of carbon dioxide released as a byproduct from the processing ofnon-fossil organic material during fermentation or other processes thatbreak down organic material into simpler molecules. Carbon dioxidesourced from non-fossil organic material is referred to herein asbiogenic carbon dioxide, as described below. Fuels or fuel intermediatescontaining biogenic carbon are known as “biofuels” or “biofuelintermediates” and the tailpipe emissions from biofuels are generallyconsidered benign to the atmosphere.

Displacing fossil-based fuel with fuel made from non-fossil organicmaterial creates atmospheric greenhouse gas (GHG) benefits by displacingcarbon dioxide emissions that would have been from the fossil fuel andwould have led to an increase in atmospheric levels of carbon dioxide.Carbon dioxide is a greenhouse gas and has been identified as acontributor to global climate change. Various governments have promotedthe increased use of renewable fuel through legislative and regulatoryregimes, including the Energy Independence and Security Act (EISA) inthe U.S. Some of the purposes of the EISA are to increase the productionof clean renewable fuels, to promote research on and deploy GHG captureand to reduce fossil fuels present in transportation fuels. In additionto EISA, numerous jurisdictions, such as the state of California, theprovince of British Columbia, Canada and the European Union, have setannual targets for reduction in average life cycle GHG emissions oftransportation fuel. Such an approach is often referred to as a LowCarbon Fuel Standard (“LCFS”), where credits may be generated for theuse of fuels that have lower life cycle GHG emissions than a specificbaseline fuel.

Despite these government incentives, biofuels still do not enjoywidespread use due to technical and cost limitations. One challenge withcommercializing biofuels is that the yield of fuel from the startingmaterial is often low. A variety of factors contribute to these lowyields. For example, in the fermentative production of ethanol fromnon-fossil organic material, such as corn, a significant amount of thecarbon from the sugar is not converted into fuel product. Duringfermentation, the yeast produces carbon dioxide in addition to thedesired ethanol product. From one mole of glucose, two moles of eachethanol and carbon dioxide are produced. This carbon is usually notcaptured as the carbon dioxide is typically vented to atmosphere due toits low energy value and, given that the carbon dioxide is biogenic, ithas no net effect on the life cycle GHG emissions of the ethanol.

Moreover, only the carbohydrate-rich portion of organic material, suchas grain or the stalks of sugar cane, is readily converted to ethanol.While the production of fuel from these parts of the plant can becarried out with relative ease, the structural parts of the plant alsocontain sugar in the form of cellulose and hemicellulose, which isgenerally more difficult to convert to biofuel. Since these parts of theplant are not converted to product in such fuel fermentation processes,this represents a significant yield loss.

Research efforts have been directed toward the development of processesthat can convert the non-edible cellulose and hemicellulose portion ofplant material to fuels. A first chemical processing step for convertingnon-edible parts of plants to ethanol, or other fermentation products,involves breaking down the fibrous material to liberate sugar monomersfrom the plant material. This can be achieved by hydrolyzing thehemicellulose first to its constituent sugars, using a chemical such assulfuric acid, followed by hydrolysis of the cellulose to glucose byenzymes referred to as cellulase enzymes. These sugars are thenfermented to ethanol with yeast or bacteria. A non-sugar containingcomponent that remains after the conversion, known as lignin, can beburned to generate heat and power for internal plant operations. Thus,the process benefits from maximizing the whole plant for fuel or energyproduction. Nonetheless, there are challenges in obtaining a high yieldof sugar for subsequent fermentation due to the recalcitrance of thecellulose to enzymatic hydrolysis. Although there is on-going researchaimed at improving the efficiency of this step, progress is slow and theprocess is still costly.

Another approach for utilizing the whole plant involves subjecting theorganic material to gasification to make syngas, which is composed ofcarbon monoxide, hydrogen and typically carbon dioxide. Syngas can thenbe used as a precursor to make additional chemicals or used as a fuelitself. While the whole plant, including both the carbohydrate andlignin components, can be converted to syngas, some of the energy storedin the sugar polymers is lost in the process. Moreover, many sideproducts are produced, including tars and carbon dioxide which are notconverted to fuel and thus contribute to yield loss.

There is thus a need in the art to overcome some of the challenges ofmaking fuels or fuel intermediates from non-fossil organic material. Aprocess for improving product yield from non-fossil organic material andmaintaining a beneficial GHG emission impact could meet this need.

SUMMARY OF THE INVENTION

The inventors have recognized that biogenic carbon dioxide producedduring the production of a fuel, fuel intermediate, chemical product orenergy product from non-fossil organic material can be collected andused as a carbon source to increase product yield and produce more fuelor fuel intermediate at lower cost. In current processes for makingfuels or other products from non-fossil organic material, carbon dioxideis frequently vented as its recovery is often perceived as impracticaldue to its low energy value and because the carbon dioxide is GHGneutral, meaning that it simply returns to the atmosphere carbon thatwas recently fixed by plants. Nevertheless, the inventors haverecognized that by collecting biogenic carbon dioxide derived fromnon-fossil organic material, and using it as a carbon source to producea biogenic carbon-based fuel or fuel intermediate, a greater amount ofthe carbon from the non-fossil organic material is converted to abiogenic carbon-based fuel or fuel intermediate. This in turn results insignificant improvements in product yield from the original non-fossilorganic material.

According to various embodiments of the present invention, the biogeniccarbon-based fuel or fuel intermediate is formed from the biogeniccarbon dioxide and hydrogen in one or more chemical and/or biologicalconversion steps, representative examples of which are described herein.The hydrogen is sourced from a process that produces fossil carbondioxide and hydrogen from a fossil fuel hydrocarbon and separates fossilcarbon dioxide from the hydrogen. The separated hydrogen, also referredto herein as “fossil derived hydrogen” is then used to make the biogeniccarbon-based fuel or fuel intermediate.

Despite being produced partially from fossil fuel hydrocarbon, thebiogenic carbon-based fuel or fuel intermediate still can have favorablelife cycle GHG emissions. While fossil derived hydrogen is used in thebiofuel production, since the hydrogen does not itself contain fossilcarbon, the carbon dioxide tailpipe emissions that result fromcombustion of the biofuel, such as in transportation vehicles, containonly or mostly biogenic carbon, and thus are considered to have aneutral effect on atmospheric carbon dioxide levels. Although the carbondioxide emissions associated with the hydrogen production from fossilfuels are included in the GHG emissions analysis, by practicingembodiments of the invention, the life cycle GHG emissions of the fuelor fuels produced can be reduced relative to a gasoline baseline, whileat the same time using a low cost fossil derived hydrogen source.

According to various embodiments of the invention, the fossil carbondioxide that is separated from the hydrogen is introduced underground.This results in the removal of the fossil carbon dioxide that mightotherwise be vented to the atmosphere, thereby reducing the life cycleGHG emission reductions associated with the biofuel or biofuelintermediate.

An additional advantage of using the fossil derived hydrogen in fuelproduction is that it possesses a high energy content, whereas theseparated fossil carbon dioxide possesses low energy content. Thus, thehigher energy hydrogen produced from fossil fuel hydrocarbon becomesincorporated into the biofuel, avoiding the detrimental tailpipeemissions of conventional fossil based fuels noted above, while the lowenergy fossil carbon dioxide is introduced underground, and does notcontribute to atmospheric carbon dioxide levels.

In certain embodiments, by conducting the foregoing process, the yieldof the biogenic carbon-based fuel or products that can be achieved fromthe non-fossil organic material can be increased by at least 10%, 25%,or 30% relative to a conventional biofuel production process. By“yield”, it means the British Thermal Units (BTU) of biogeniccarbon-based fuel that can be produced from a given weight of rawmaterial, as measured using the “Low Heating Value” using ASTMmethodology known in the art. For instance, if ethanol is the biogeniccarbon-based fuel produced by the process, the total amount of ethanolproduced can be increased by 10% or more relative to a conventional cornethanol production process in which biogenic carbon dioxide is notcollected.

Further, by using fossil derived hydrogen and biogenic carbon dioxide toform a fuel or fuel intermediate as described herein, embodiments of thepresent invention can provide for even greater increases in productyield from the original non-fossil organic material than conventionalprocesses for producing a biofuel from such material. In certainembodiments as set forth further herein, by virtue of adding fossilderived hydrogen energy to make biofuel, for example ethanol, the yieldconventionally referred to as “theoretical yield”, which is the yieldbased on the amount of product that would be formed if the fermentationreaction went to completion, can be exceeded.

Thus, according to a first aspect of the invention, there is provided aprocess for producing a fuel or fuel intermediate containing carbonderived from non-fossil organic material for fuel production comprising:(i) providing biogenic carbon dioxide that is sourced from a productionprocess comprising a step of fermentation, said production processproducing a first product derived from the non-fossil organic material,the first product selected from: (a) an energy product; (b) a biogeniccarbon-based product selected from a chemical product, a fuel and a fuelintermediate; and (c) a combination thereof, wherein biogenic carbondioxide is generated during the production process and collected; (ii)providing a stream enriched in hydrogen that is sourced from a hydrogenproduction process comprising the steps of: (a) converting fossilmethane to carbon monoxide and hydrogen by reforming, (b) converting atleast a portion of the carbon monoxide by a water-gas shift reaction tocarbon dioxide, thereby producing a stream comprising fossil carbondioxide and hydrogen, and (c) separating at least a portion of thehydrogen from the stream of step (b) from non-hydrogen components toproduce the stream enriched in hydrogen and a stream comprising fossilcarbon dioxide; (iii) converting the biogenic carbon dioxide from step(i) and hydrogen produced in step (ii)(c) to a second product by aprocess comprising at least one chemical or biological conversion,wherein the second product so produced is a biogenic carbon-based fuelor fuel intermediate; and (iv) carrying out or arranging for one or moreparties to carry out at least one step that contributes to a reductionin the life cycle GHG emissions of a fuel or a fuel made from a fuelintermediate produced by the process, wherein the life cycle GHGemissions are reduced by at least 20% relative to a gasoline baseline,the at least one step selected from: (a) introducing at least a portionof fossil carbon dioxide recovered from one or more streams comprisingfossil carbon dioxide generated during the hydrogen production processinto an apparatus for transporting carbon dioxide, withdrawing carbondioxide from the apparatus and introducing the withdrawn carbon dioxideunderground, and (b) using at least a portion of the first productselected from a chemical and energy product to displace the use orproduction of a corresponding fossil-based product, wherein the lifecycle GHG emissions of the fuel are measured by EPA methodology asdescribed herein.

According to a second aspect, the present invention provides a processfor using biogenic carbon dioxide derived from non-fossil organicmaterial for fuel production comprising: (i) providing biogenic carbondioxide that is sourced from a production process comprising a step offermentation, the production process producing a first product derivedfrom the non-fossil organic material, the first product selected from:(a) an energy product; (b) a biogenic carbon-based product selected froma chemical product, a fuel and a fuel intermediate; and (c) acombination thereof, wherein biogenic carbon dioxide is generated duringthe production of the first product and collected; (ii) providing astream enriched in hydrogen that is sourced from a hydrogen productionprocess comprising the steps of: (a) converting fossil methane to carbonmonoxide and hydrogen by reforming; (b) converting at least a portion ofthe carbon monoxide by a water-gas shift reaction to carbon dioxide,thereby producing a stream comprising carbon dioxide and hydrogen, and(c) separating at least a portion of the hydrogen from the stream ofstep (b) from non-hydrogen components to produce the stream enriched inhydrogen and a stream comprising fossil carbon dioxide; (iii) convertingthe biogenic carbon dioxide from step (i) and hydrogen produced in step(ii)(c) to a second product by a process comprising at least onechemical or biological conversion, wherein the second product soproduced is a biogenic carbon-based fuel or fuel intermediate; and (iv)generating or causing the generation of a biofuel credit as a result ofproducing the second product.

According to a third aspect of the invention, there is provided aprocess for using biogenic carbon dioxide derived from non-fossilorganic material for fuel production comprising: (i) providing biogeniccarbon dioxide that is sourced from a production process comprising astep of fermentation; (ii) providing a stream enriched in hydrogen thatis sourced from a hydrogen production process comprising the steps of:(a) converting fossil methane to carbon monoxide and hydrogen byreforming, (b) converting at least a portion of the carbon monoxide by awater-gas shift reaction to carbon dioxide, thereby producing a streamcomprising carbon dioxide and hydrogen, and (c) separating at least aportion of the hydrogen from the stream of step (b) from non-hydrogencomponents to produce the stream enriched in hydrogen; and (iii)converting the biogenic carbon dioxide from step (i) and hydrogenproduced in step (ii)(c) to a biogenic carbon-based fuel or fuelintermediate.

In embodiments of any of the foregoing aspects of the invention, theproduction process of step (i) produces an alcohol or an organic acid.The alcohol may be ethanol. In yet further embodiments, at least aportion of the biogenic carbon dioxide provided in step (i) is sourcedfrom (a) a fermentation to produce the ethanol, (b) an anaerobicdigestion of a process stream resulting after a step of recovering theethanol, or (c) a combination thereof. In addition to producing ethanol,the production process of step (i) may further comprise the productionof lignin.

In further embodiments of any of the foregoing aspects of the invention,the production process of step (i) produces at least one energy productthat is steam, electricity, methane or lignin.

According to a further embodiment, a fuel or fuel intermediate isproduced in the production process of step (i) that is the same type asthe biogenic carbon-based fuel or fuel intermediate produced in step(iii).

In certain embodiments of any of the foregoing aspects of the invention,the biogenic carbon-based fuel or fuel intermediate of step (iii) is analcohol, including ethanol or methanol.

In further embodiments, the biogenic carbon-based fuel or fuelintermediate of step (iii) is a liquid or gaseous hydrocarbon at 20° C.The hydrocarbon may be selected from methane and gasoline.Alternatively, the hydrocarbon may be a liquid hydrocarbon produced by aFischer Tropsch reaction.

In further embodiments of any of the foregoing aspects of the invention,step (iii) comprises a biological conversion that is a fermentation. Thefermentation may produce an alcohol such as ethanol.

In another embodiment of the invention, the production process of step(i) is an ethanol production process comprising a step of producingbiogenic ethanol from a fermentation and wherein the biogenic carbondioxide is generated during the ethanol production process andcollected, and wherein step (iii) comprises introducing biogenic carbondioxide from step (i) and hydrogen from step (ii) together or separatelyto a fermentation reactor and forming additional biogenic ethanol byconverting the biogenic carbon dioxide and hydrogen in the reactor tobiogenic ethanol by fermentation with a microorganism. The biogeniccarbon dioxide and hydrogen may be introduced together or separatelywith a fermentation broth.

Embodiments of the first and third aspect of the invention may furthercomprise carrying out or arranging for one or more parties to carry outat least one step that contributes to a reduction in the life cycle GHGemissions of a fuel or a fuel made from a fuel intermediate produced bythe process, wherein the life cycle GHG emissions of the fuel are atleast 20% lower than a gasoline baseline, the at least one step selectedfrom: (a) introducing at least a portion of fossil carbon dioxiderecovered from one or more streams comprising fossil carbon dioxidegenerated during said hydrogen production process into an apparatus fortransporting carbon dioxide, withdrawing carbon dioxide from theapparatus and introducing the withdrawn carbon dioxide underground, and(b) using at least a portion of a product produced in the productionprocess of step (i) selected from a chemical and energy product todisplace the use or production of a corresponding fossil-based product.In one embodiment, the life cycle GHG emissions are measured by EPAmethodology. In an alternative embodiment, the life cycle GHG emissionsare measured by LCFS methodology.

In further embodiments of the first and third aspect of the invention, abiofuel credit is generated or caused to be generated. The biofuelcredit may be a Renewable Identification Number (RIN) or an LCFS credit.

In certain embodiments of any of the foregoing aspects of the invention,the amount of biogenic carbon in the second biogenic carbon-based fuelor fuel intermediate may be between 72 mole % and 100 mole %, between 75mole % and 100 mole %, between 80 mole % and 100 mole %, between 85 mole% and 100 mole %, between 90 mole % and 100 mole % or between 95 mole %and 100 mole % (mol:mol of biogenic:non-biogenic carbon).

According to a fourth aspect of the invention, there is provided aprocess for increasing biogenic ethanol production from non-fossilorganic material comprising: (i) providing biogenic carbon dioxide thatis sourced from an ethanol production process comprising producingbiogenic ethanol from a fermentation of the non-fossil organic material,wherein biogenic carbon dioxide is generated during the ethanolproduction process and collected; (ii) providing a stream comprisinghydrogen that is sourced from a process that produces fossil carbondioxide and hydrogen from a fossil-fuel hydrocarbon, the streamcomprising a molar ratio of hydrogen to fossil carbon monoxide andcarbon dioxide of greater than 4:1; (iii) introducing biogenic carbondioxide from step (i) and hydrogen from step (ii) together or separatelyto a fermentation reactor; and (iv) forming additional biogenic ethanolby converting the biogenic carbon dioxide and hydrogen in the reactor tobiogenic ethanol by fermentation with a microorganism.

According to a fifth aspect of the invention, there is provided aprocess for increasing biogenic ethanol production from non-fossilorganic material comprising: (i) providing biogenic carbon dioxide thatis sourced from an ethanol production process comprising producingbiogenic ethanol from a fermentation of the non-fossil organic material,wherein biogenic carbon dioxide is generated during the ethanolproduction process and collected; (ii) providing a stream enriched inhydrogen that is sourced from a hydrogen production process comprisingthe steps of: (a) converting fossil methane to carbon monoxide andhydrogen by reforming; (b) converting at least a portion of the carbonmonoxide by a water-gas shift reaction to produce a stream comprisingfossil carbon dioxide and hydrogen; and (c) separating at least aportion of the hydrogen from the stream to produce the stream enrichedin hydrogen; (iii) introducing biogenic carbon dioxide from step (i) andhydrogen produced in step (ii)(c) together or separately to afermentation reactor; and (iv) forming additional biogenic ethanol byconverting the biogenic carbon dioxide and hydrogen in the reactor toethanol by fermentation with a microorganism.

In certain embodiments of any of the foregoing aspects of the invention,the stream enriched in hydrogen or comprising hydrogen has a molar ratioof hydrogen to the combined amount of fossil carbon monoxide and carbondioxide of greater than 5:1, greater than 6:1, greater than 7:1, greaterthan 8:1, greater than 10:1 or greater than 15:1.

In further embodiments of any of the foregoing aspects of the invention,the stream enriched in hydrogen or a stream comprising hydrogen containsless than 5 mole % fossil carbon, less than 3 mole % fossil carbon, lessthan 2 mole % fossil carbon, less than 1 mole % fossil carbon or lessthan 0.5 mole % fossil carbon.

In yet further embodiments of any of the foregoing aspects of theinvention, the stream enriched in hydrogen or a stream comprisinghydrogen contains greater than 90 mol %, 93 mol %, 95 mol %, 96 mol %,97 mol %, 98 mol % or 99 mol % hydrogen (mol:mol).

In those embodiments of the invention in which ethanol is produced, theamount of biogenic carbon in the additional biogenic ethanol produced instep (iv) above may be between 70 and 100 mole %, between 75 mole % and100 mole %, between 80 mole % and 100 mole %, between 85 mole % and 100mole %, between 90 mole % and 100 mole % or between 95 mole % and 100mole % (mol:mol of biogenic and non-biogenic carbon).

According to another aspect of the present invention there is provided aconversion process comprising: (a) producing or causing one or moreparties to produce a first fuel, fuel intermediate, chemical product orenergy product and biogenic carbon dioxide from non-fossil organicmaterial; (b) providing biogenic carbon dioxide that has been recoveredfrom step (a); (c) converting or causing one or more parties to convertthe biogenic carbon dioxide derived from the non-fossil organic materialinto a second fuel in one or more biologic and/or chemical conversionsteps, wherein such fuel has a heat of combustion of at least 22 MJ/kg,measured as a Low Heating Value by standard ASTM methodology, andwherein the conversion process incorporates hydrogen from fossil fuelthat has had fossil carbon dioxide removed; and (d) optionallygenerating or causing the generation of a fuel credit as a result of thefavorable GHG emissions profile of a fuel produced by the process.

The present invention will be described with regard to furtherembodiments. However, it will be apparent to persons skilled in the artthat a number of variations and modifications can be made withoutdeparting from the scope of the invention as defined in the claims.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a process flow diagram showing the production of biogenicethanol using fossil derived hydrogen and biogenic carbon dioxide in aprocess in which fossil carbon dioxide from hydrogen production isintroduced underground.

FIG. 2 is a process flow diagram showing the production of ethanol usingsyngas from fossil fuel and biogenic carbon dioxide.

FIG. 3 is a process flow diagram showing the production of biogenicethanol using fossil derived hydrogen and biogenic carbon dioxide in aprocess in which electricity derived from lignin displaces fossilderived electricity from a coal burning power plant.

FIG. 4 is a process flow diagram showing the production of biogenicgasoline using fossil derived hydrogen and biogenic carbon dioxide.

FIG. 5 is a process flow diagram showing streams from which carbondioxide can be recovered during a hydrogen production process forintroduction underground.

DETAILED DESCRIPTION

Non-Fossil Organic Material

In various embodiments the processes described herein produce a firstenergy product or a biogenic carbon-based product selected from achemical product, a fuel and/or a fuel intermediate and carbon dioxidefrom non-fossil organic material.

The term, “biogenic carbon-based” in reference to a product, such as afuel, fuel intermediate or a chemical product, means that the productcomprises carbon that is sourced directly or indirectly from non-fossilorganic material. This can include carbon derived from fossil carbondioxide, or from both fossil and non-fossil carbon dioxide, but that isconsidered biogenic by those skilled in the art, as described furtherherein.

As used herein, the term “non-fossil organic material” or simply“organic material” refers to a material comprising carbon from one ormore biologic sources that is not obtained from underground geologicformations. Any suitable non-fossil, biologic source material obtainedor derived directly or indirectly from plants or animals can be used asthe organic material in embodiments of the process of the invention toprovide a carbon and/or energy source. This includes plant derivedorganic material comprising polysaccharides, including starch, celluloseand hemicellulose, oligosaccharides, disaccharides, monosaccharides, ora combination thereof. Other biologic, non-fossil source material thatcan be utilized as a carbon and/or energy source includes compounds ormolecules derived from non-sugar containing material, such as lignin andfats. The organic material may be in liquid form containing solublecomponents, solid form, gaseous form, or any combination thereof.

According to an embodiment of the invention, the organic materialincludes material comprising starches, sugars or other carbohydratesderived from sugar or starch crops. The sugar or starch crops mayinclude, but are not limited to, corn, wheat, barley, rye, sorghum,rice, potato, cassava, sugar beet, sugar cane, or a combination thereof.

The non-fossil organic material may also be biomass or biomass derivedmaterial. Examples of biomass and biomass derived material include (i)energy crops; (ii) residues, byproducts or waste from the processing ofplant material in a facility, or feedstock derived therefrom; (iii)agricultural residues; (iv) forestry material; (v) material derived frompulp and paper processing; (vi) pulp and paper residues; and (vii)municipal waste or components removed or derived from municipal waste.The biomass or biomass derived material can be in any form, includingsolid, liquid, gaseous form or a combination thereof.

Energy crops include biomass crops such as grasses, including C4grasses, such as switch grass, energy cane, sorghum, cord grass, ryegrass, miscanthus, reed canary grass, C3 grasses such as Arundo donax ora combination thereof.

Residues, byproducts or waste from the processing of plant material in afacility or feedstock derived therefrom include residues remaining afterobtaining sugar from plant biomass such as sugar cane bagasse, sugarcane tops and/or leaves, beet pulp, or residues remaining after removingsugar from Jerusalem artichoke or residues remaining after grainprocessing, such as corn fiber, corn stover or bran from grains.Agricultural residues include, but are not limited to soybean stover,corn stover, rice straw, sugar cane tops and/or leaves, rice hulls,barley straw, corn cobs, wheat straw, canola straw, oat straw, oathulls, or corn cobs.

Forestry material includes any species of hardwood or softwood. The termincludes residues, byproducts, waste or non-waste material fromprocessing any hardwood or softwood species. Examples of waste includeresidues from sawmills, trimmings or slash from logging operations. Pulpand paper residue, includes non-pulp and non-paper products fromchemical pulping or paper making such as black liquor, spent sulfiteliquor, sludge, broke, fines or precipitated lignin.

Municipal waste includes post-consumer material or waste from a varietyof sources, such as domestic, commercial, institutional and industrialsources. For example, the term includes refuse from waste collection,raw sewage and sewage sludge.

Biomass or biomass derived material can be a mixture of fibers thatoriginate from different kinds of plant material, including mixtures ofcellulosic and non-cellulosic biomass. In addition, the biomass maycomprise fresh biomass, partially dried biomass, fully dried biomass, ora combination thereof. Moreover, new biomass varieties may be producedfrom any of those listed above by plant breeding or by geneticengineering.

First Energy Product or Biogenic Carbon-Based Product

Certain embodiments of the invention comprise producing or causing oneor more parties to produce a first product that is derived or sourcedfrom non-fossil organic material. The first product is selected from (a)an energy product; and (b) a biogenic carbon-based product selected froma fuel, fuel intermediate and a chemical product. The fuel or fuelintermediate is also referred to herein as a biofuel or biofuelintermediate, respectively.

As used herein, an “energy product” is (i) any product that is used togenerate electrical energy or heat, such as lignin or methane; or (ii)products that store heat energy or electrical energy including steam andelectricity produced by combusting non-fossil organic material.

A “fuel” includes liquid or gaseous material which contains carbon thatcan be combusted to produce power or heat and includes bothtransportation and heating fuel. The fuel may be a liquid at 20° C.,such as an alcohol, or a gaseous fuel, such as methane or hydrogen,which are gases at this temperature. The fuel may exist in any form,including gaseous, liquid or compressed form.

A “fuel intermediate” is a precursor used to produce a fuel by a furtherconversion process, such as by a biologic conversion, a chemicalconversion, or a combination thereof.

A “chemical product” is a chemical compound used in a production processor a product such as a commodity. Examples of chemical products producedfrom non-fossil organic material are sugar acids, sugar alcohols,organic acids, bioplastic or bioplastic intermediates,fermentation-derived chemicals, fertilizer and lignin-based products. A“lignin-based product” is a product that comprises lignin, a ligninderivative, or a product that is produced from lignin.

Examples of fuels, fuel intermediates, chemical and energy products, andprocesses for their production from non-fossil organic material aredescribed below. Such processes include fermentation to produce liquidor gaseous fermentation products, or thermal processes, includingcombustion, gasification, pyrolysis or a combination thereof.

Fermentation

The fuel, fuel intermediate and/or chemical product may be produced byfermentation using any of a number of known processes that use bacteria,yeast or other microorganisms. As used herein, “fermentation” includesthe biologic conversion of non-fossil organic material by any processusing microbes in one or more stages. Such term includes thefermentation of non-fossil organic material in any form, includingsolid, liquid or gaseous forms, or any combination thereof. In additionto producing a fuel, fuel intermediate or chemical product, processescomprising fermentation can generate one or more energy products such aslignin, methane, steam or electricity for external use.

Carbon dioxide is often generated during the fermentation and may becollected using known processes as discussed further herein. Forexample, in the production of ethanol, the fermentation of glucoseproduces two molecules of carbon dioxide by the following reaction:C₆H₁₂O₆→2C₂H₆O+2CO₂

Prior to fermentation, the non-fossil organic material may be processedby mechanical, chemical, thermal and/or biologic processes to improveits ability to be fermented. In some embodiments of the invention, thenon-fossil organic material is a sugar or starch crop. For a sugar crop,the non-fossil organic material is typically processed to extract sugartherefrom. The sugar is subsequently fermented to produce the fuel, fuelintermediate or chemical product. Sugar crops, including, but notlimited to, sugar cane, sugar beets or sweet sorghum, may be subjectedto a mechanical treatment, such as crushing and/or pressing, to extractthe sugar from the plants. For example, sucrose from sugar cane can beextracted using roller mills. Sugar from sweet sorghum stalks can beextracted in a similar manner, although certain varieties of sorghumcontain grain that can be processed using technology employed forprocessing starch crops as described below.

Starch crops, which include cereal crops, may be subjected to sizereduction, such as by milling or grinding. The starch may besubsequently hydrolyzed with enzymes, by chemical treatment, or acombination of these treatments. By way of example, grain may be milledwith a roller or hammer mill, followed by the addition of water andhydrolysis of the starch with amylases to produce fermentable sugar.This method is commonly referred to as “dry milling”. An alternativemethod is “wet milling” in which the grain is steeped, such as in anacidic solution and/or a solution containing enzymes, and then subjectedto size reduction, such as milling, to facilitate separation of thestarch from the other components of the grain. The starch issubsequently hydrolyzed to sugar using methods described above.

Sugar for fermentation can also be obtained from processes that convertthe cellulose and hemicellulose portion of plant material to the fuel,fuel intermediate or chemical product. Processing may includepretreating a biomass or biomass derived material to disrupt fiberstructure. Pretreatment can be with heat, mechanical processing,addition of one or more chemicals, biocatalysts, or combinations thereofto release sugars. After pretreatment, between 30 wt % and 100 wt % ofthe xylan from the hemicellulose may be hydrolyzed, although, duringsome pretreatments, there may be limited xylan hydrolysis. Afterpretreatment, between 10 wt % and 100 wt % of the lignin may remaininsoluble. The lignin may be used to generate an energy product orchemical product, as set forth below.

Non-limiting examples of pretreatment include acid pretreatment, alkalipretreatment and hydrothermal pretreatment. Such pretreatment processesare set forth in U.S. Application No. 61/948,726 filed Mar. 6, 2014,which is incorporated herein by reference.

The pretreatment may improve the accessibility of cellulose to asubsequent enzymatic or chemical hydrolysis to convert cellulose toglucose. The enzymatic hydrolysis may involve the addition of enzymesincluding cellulases and hemicellulases. Other enzymes that may be usedinclude amylases, glucanases, proteases, lipases, pectinases, laccases,phytases or combinations thereof. The glucose may then be converted tothe fuel, fuel intermediate or chemical product.

In certain embodiments of the invention, the fermentation processproduces liquid fuels, fuel intermediates or chemical products. Suchliquid products include fuels or fuel intermediates including alcohols,such as ethanol, propanol, butanol and isobutanol. For ethanolproduction, the fermentation can be carried out with a yeast or abacterial strain, such as a Saccharomyces spp. or Zymomonas mobilisstrain. Butanol may be produced from glucose by a microorganism such asClostridium acetobutylicum and then concentrated by distillation. Thealcohol may then be distilled to obtain a concentrated ethanol solution.

Xylose, arabinose and other sugars that are derived from thehemicelluloses may also be fermented to fuels, fuel intermediates orchemical products. An example of a fuel is ethanol, which can beproduced by a yeast strain that naturally contains, or has beenengineered to contain, the ability to ferment these sugars to ethanol.Non-limiting examples of microbes that have been genetically modified toferment xylose include recombinant Saccharomyces strains into which hasbeen inserted either (a) the xylose reductase (XR) and xylitoldehydrogenase (XDH) genes from Pichia stipitis (see for example U.S.Pat. Nos. 5,789,210, 5,866,382, 6,582,944 and 7,527,927 and EuropeanPatent No. 450530) or (b) fungal or bacterial xylose isomerase (X1) gene(see for example U.S. Pat. Nos. 6,475,768 and 7,622,284). Examples ofyeasts that have been genetically modified to ferment L-arabinoseinclude, but are not limited to, recombinant Saccharomyces strains intowhich genes from either fungal (see for example U.S. Pat. No. 7,527,951)or bacterial (see for example WO 2008/041840) arabinose metabolicpathways have been inserted.

Although examples of fuels and fuel intermediates are provided,embodiments of the present invention also encompass the production ofchemical products from the fermentation of organic material. Examples ofchemical products that can be produced by fermentation include sugaracids including xylonic acid and arabonic acid; sugar alcohols includingxylitol, arabitol, erythritol, galactitol and mannitol; and organicacids including adipic acid, citric acid, malic acid, succinic acid,pyruvic acid, acetic acid, itaconoic acid and lactic acid; biooilsincluding sesquiturpenes such as farnesene; diols, including butanedioland 1,3 propanediol; alcohols, such as propanol; and ketones, includingacetone. Examples of processes for producing such chemical products byfermentation from organic material are set forth in U.S. Publication No.2012/0231514 (published Sep. 13, 2012).

During the production of a fuel, fuel intermediate and/or chemicalproduct from biomass or biomass derived material, a non-sugar containingcomponent that remains after the conversion, known as lignin, can becombusted to generate an energy product including heat or power. Suchcombustion processes are discussed further below. Recovered lignin mayalso be utilized for making a chemical product, such as lignin-basedproduct. The lignin-based product may be an additive in a commercialapplication, a dispersant, a binder or an adhesive. An example of aconversion process is heating lignin at elevated temperature in agasification or pyrolysis to produce aromatic compounds such as phenols.

Although the fermentation of organic material in the form of sugar isdescribed, the fermentation may also involve the conversion of organicmaterial in the form of a gaseous stream to a fuel, fuel intermediateand/or chemical product. A non-limiting example of such a fermentationis the production of ethanol from syngas, examples of which aredescribed in more detail herein. These processes may produce carbondioxide that can be collected as used to produce a fuel or fuelintermediate.

The fermentation may also be an anaerobic digestion, which is thebiologic breakdown of non-fossil organic material by microorganismsgenerally under low oxygen conditions, or in the absence of oxygen, toproduce gases. Prior to anaerobic digestion, the non-fossil organicmaterial is optionally processed by mechanical, chemical, thermal and/orbiologic processes to improve its ability to be fermented. Biologicprocesses include treatment with enzymes including cellulases,hemicellulases, amylases, glucanases, proteases, lipases, pectinases,laccases, phytases or combinations thereof.

The gases produced by anaerobic digestion of non-fossil organic materialinclude methane, biogenic carbon dioxide and hydrogen. As would beappreciated by those skilled in the art, anaerobic digestion may involvethe decomposition of non-fossil organic material, includingcarbohydrates, fats and proteins therein, into simple sugars andglycerol. These compounds are then converted to acids, which aresubsequently converted into methane by methanogenic bacteria or othermicroorganisms, typically by the following reaction:C₆H₂O₆→3CH₄+3CO₂

The gases from anaerobic digestion, also referred to herein as “biogas”,include methane, carbon dioxide and typically one or more impurities.Generally, after collection of carbon dioxide, and removal of one ormore impurities, the methane can be used as compressed natural gas orliquid natural gas to power vehicles or used for heating. Alternatively,the methane from biogas can be used to produce another fuel, fuelintermediate and/or chemical product.

The methane from biogas may be introduced to an apparatus fortransporting methane, such as a pipeline. Methane may then be withdrawnfrom the apparatus for use as a transportation or heating fuel or foruse in the production of another fuel or fuel intermediate. Governmentauthorities have recognized that it does not make any difference, interms of the beneficial environmental attributes associated with the useof biogas, whether the displacement of fossil fuel occurs in a fungiblenatural gas pipeline, or through the use of the biogas itself as atransportation or heating fuel. Thus, when fossil fuel such as methaneis obtained from biogas, and transported (such as via a natural gaspipeline), a corresponding amount of withdrawn fuel (such as methane) isconsidered renewably derived or to have the GHG emission attributes ofthe biogas introduced to the pipeline, even if is the molecules thereinare fossil derived. Thus, for example, methane obtained directly frombiogas or fossil methane qualifying as renewable is referred to hereinas “methane sourced from biogas”.

Fuels or fuel intermediates produced directly or indirectly from methanesourced from biogas include syngas, hydrogen or liquid hydrocarbons.Syngas, which comprises hydrogen, carbon monoxide and optionally othergaseous components, including carbon dioxide, can be used as a fuelitself or more typically as an intermediate to produce another fuel orfuel intermediate. Syngas can be produced from methane sourced frombiogas by steam methane reforming by the following reaction:CH₄+H₂O→CO+3H₂

Syngas can also be produced by thermal processing as described below.The use of syngas to produce other fuels or fuel intermediates isdescribed below.

In certain embodiments, hydrogen is produced from methane sourced frombiogas. Renewable hydrogen may be produced from the methane by steammethane reforming, typically followed by a water gas shift (WGS)reaction. Those skilled in the art understand that a WGS reactioninvolves the chemical reaction of carbon monoxide and water vapor toform carbon dioxide and hydrogen. After production, such hydrogen may beused in a process to produce a liquid transportation or heating fuel.For example, the renewable hydrogen may be combined with a crude oilderived liquid hydrocarbon in a hydrogen addition step in a fuelproduction facility, such as an oil refinery, so that it becomesincorporated into the hydrocarbon and ultimately becomes part of a fuelthat is the product of the facility. Examples of such processes are setforth in U.S. Pat. Nos. 8,658,026 and 8,753,854 which are incorporatedherein by reference in their entireties and particularly for the purposeof describing such processes. The renewable hydrogen used in theforegoing process may include hydrogen from methane sourced from biomassconsidered renewable by regulators.

Thermal Process

The non-fossil organic material may be subjected to a thermal process toproduce a fuel, fuel intermediate, chemical product and/or an energyproduct. The thermal process includes combustion, gasification,pyrolysis or a combination thereof. An energy product may be produced bycombustion of the non-fossil organic material, while a fuel, fuelintermediate or chemical product may be produced by gasification orpyrolysis. Examples of fuels, fuel intermediates or chemical productsproduced from the gasification or pyrolysis of non-fossil organicmaterial include syngas, hydrogen, methane, liquid hydrocarbons,pyrolysis oil and ammonia. Examples of combustion, gasification andpyrolysis, and products generated from these processes, are described inmore detail below.

Combustion includes one or more exothermic reactions between thenon-fossil organic material and an oxidant, which is typically air oroxygen. Combustion of the non-fossil organic material can be conductedin a power plant. In such embodiments, carbon dioxide is recovered froma gas stream, known in the art as “flue gas”.

The combustion may be carried out with a gas having an oxygen contentexceeding that of air, known in the art as an “oxyfuel combustionprocess”. In certain embodiments of the invention, the flue gas may bere-circulated to the combustion and mixed with an oxygen stream as partof the oxyfuel combustion process. An advantage of oxyfuel combustionprocesses is that combusting in the presence of oxygen removescontaminants. The result is a flue gas having a high concentration ofcarbon dioxide, which may be collected with relative ease.

The non-fossil organic material is combusted to produce an energyproduct. Typically, the non-fossil organic material that is combusted isbiomass or biomass derived material. An example of a biomass derivedmaterial suitable for combustion is lignin or a stream that compriseslignin as a constituent. Lignin differs from cellulose and hemicellulosein that it is not composed of sugar units, but rather phenolic-propaneunits. Although lignin does not yield any fermentable sugars, it may becombusted to generate heat or electricity.

The non-fossil organic material may be fed to a combustion apparatus,such as a steam boiler and the heat generated utilized to produceelectricity, steam, process heat, building heat, or any combination ofthereof. The boiler generally includes a section in which water or otherfluid is heated. The heat produced from the burning of organic materialmay be transferred to boiler feed water to produce steam. The boiler maybe a fluidized bed boiler, although other types of boilers may be usedas required. The feed to the boiler may also include biogas producedduring anaerobic digestion. Moreover, during the start-up stage of theprocess, a small amount of natural gas may be added to the boiler toheat the fuel to the ignition point. Depending on the emissionsregulations, exhaust from the boiler may be passed to a scrubber orother series of operations to reduce pollutant levels before beingdischarged to the environment. As well, particulate matter may need tobe removed from the exhaust. Ash from the boiler may be landfilled orsold as a co-product depending on its composition.

The steam may be used to drive turbines to create electricity for saleto the power grid and/or to meet plant needs. Alternatively, or inaddition to electricity generation, the steam can be used to supplyprocess heat needs within a plant. If the steam is used within a plant,the pressure may be reduced prior to its re-use in the process.Furthermore, the steam can be utilized to provide building heating.

While combustion produces an energy product, gasification is typicallycarried out to produce syngas. Gasification includes heating at elevatedtemperature, generally in the presence of oxygen. Gasification ofbiomass or biomass derived products can be carried out by the followingreaction:8CH₂O+O₂→6CO+2CO₂+8H₂

The carbon dioxide produced by the above reaction can be collected asset out below. The syngas can, in turn, be used as an intermediate toproduce another fuel or fuel intermediate, as set forth previously, orused as a fuel itself. Examples of products made directly or indirectlyfrom syngas include liquid hydrocarbons, methane, hydrogen, methanol andethanol. Processes for their production from syngas are described above.

Biogenic carbon dioxide can be collected from one or more stages of agasification process or downstream stages, such as product synthesisprocesses and converted to the second biogenic carbon-based fuel or fuelintermediate as described below. Without being limiting, the biogeniccarbon dioxide may be collected from a waste gas stream that remainsafter combustion of a gas stream containing both combustible gases andcarbon dioxide. Burning of the combustible gases in the mixture formscarbon dioxide and the resulting stream enriched in carbon dioxide cansubsequently be used to make the biogenic carbon-based fuel or fuelintermediate. Biogenic carbon dioxide may also be separated andrecovered from syngas. Further, during a syngas fermentation, which isdescribed further below, carbon dioxide generated during thefermentation can be collected and used for production of the fuel orfuel intermediate. Carbon dioxide can also be collected from a streamresulting from subjecting syngas to a water gas shift reaction, asfollows:CO+H₂O→CO₂+H₂

One or more of the above-mentioned streams produced from thegasification or product synthesis to fuel can be combined and then usedfor additional fuel or fuel intermediate production.

Pyrolysis includes heating non-fossil organic material at elevatedtemperature to produce syngas, char and/or pyrolysis oil and may becarried out in the absence of oxygen or at low levels thereof. Carbondioxide can be collected from a stream resulting from a water gas shiftreaction carried out on the syngas or other streams generated during theprocess that contain carbon dioxide. Pyrolysis oil, also referred to asbio-oil, is produced by subjecting the non-fossil organic material topyrolysis at elevated temperature, typically lower than gasification.Pyrolysis oil can be treated further to produce a transportation fuelsuch as diesel or used directly as a fuel.

Producing Fuels from Fuel Intermediates

As described above, syngas can originate from a variety of differentprocesses, including gasification, pyrolysis or produced from methanesourced from biogas. Examples of products made directly or indirectlyfrom syngas include liquid hydrocarbons, methane, hydrogen, methanol,ethanol or ammonia.

The production of liquid hydrocarbons from syngas may be advantageous inthat they can replace petroleum products such as diesel or gasoline.Hydrocarbons can be produced by a Fischer Tropsch process which uses acatalyst to convert carbon monoxide in syngas to hydrocarbons, such asalkanes, although other reaction products may result as well.

In an embodiment of the invention, methane is produced from syngas. Theproduction of methane from syngas includes a methanation reaction, whichis conducted over metal catalysts at elevated temperature and pressure.The chemical reaction for producing methane from syngas is as follows:CO+3H₂→CH₄+H₂O

In another embodiment of the invention, methane is produced from carbondioxide and hydrogen present in syngas by the following reaction:CO₂+4H₂→CH₄+2H₂O

Renewable hydrogen can also be produced by syngas by subjecting thesyngas to a water gas shift reaction, as follows:CO+H₂O→CO₂+H₂The renewable hydrogen can be used directly as a transportation fuel orused in a fuel production process to produce a hydrocarbon fuel, forexample as described in U.S. Pat. Nos. 8,658,026 and 8,753,854.

Another product that can be produced from syngas is methanol. Thereaction is as follows:CO+2H₂→CH₃OH

As would be appreciated by those of skill in the art, generally carbondioxide is added to the syngas or a certain amount of carbon dioxide isleft in the syngas to maintain a suitable reaction stoichiometry foroptimal methanol production. The methanol produced from this reactioncan be converted to ethanol or other fuels through a variety ofdifferent chemical or biological conversion routes, representativeexamples of which are described further below.

Collecting Biogenic Carbon Dioxide

As mentioned, biogenic carbon dioxide is generated during the productionof the first energy product or biogenic carbon-based product. Thoseskilled in the art will appreciate that, in the practice of theinvention, the biogenic carbon dioxide can be sourced directly from aproduction process using non-fossil organic material as a feedstock orit can be fossil carbon dioxide, or a mixture of fossil and non-fossilcarbon dioxide that is sourced more indirectly from such organicmaterial. Thus, “biogenic carbon dioxide” as used herein includes carbondioxide that is (a) obtained from a production process using non-fossilorganic material as a feedstock; (b) withdrawn from an apparatus fortransporting carbon dioxide, which withdrawn carbon dioxide is fromfossil sources or contains a mixture of carbon dioxide from fossil andnon-fossil sources and that is considered renewable due to theintroduction of an amount of carbon dioxide produced by such productionprocess to the apparatus that corresponds to the amount of carbondioxide withdrawn; or both (a) and (b).

The biogenic carbon dioxide generated during the production of the firstenergy product of biogenic carbon-based product is “collected”, by whichit is meant any suitable process for obtaining carbon dioxide during orafter its generation, and may include single or multi-stage processes.The biogenic carbon dioxide may be collected along with other non-CO₂components. That is, collection of carbon dioxide may comprise obtaininga stream comprising biogenic carbon dioxide and optionally one or morenon-CO₂ components. To illustrate, collecting a crude biogas stream,from a landfill or a digester, comprising carbon dioxide along withother components such as methane and hydrogen resulting from anaerobicdigestion constitutes collection of biogenic carbon dioxide. To furtherillustrate, collecting carbon dioxide may comprise obtaining a streamcomprising carbon dioxide enriched by recycle.

The biogenic carbon dioxide may be enriched by purification, recycle orthe like. The purification may, for instance, include a process in whichcarbon dioxide is separated from other constituents in a stream or otherprocesses that produce a stream enriched in carbon dioxide. Such otherprocesses include combusting a carbon dioxide-containing streamcomprising combustible carbon to produce a stream comprising additionalcarbon dioxide resulting from the combustion. Recycling of a streamcomprising carbon dioxide may result in enrichment of carbon dioxide aswell due to the increase in concentration of carbon dioxide duringre-circulation. A stream enriched in biogenic carbon dioxide may also bea waste stream generated during the process.

The CO₂-enriched stream may comprise at least 60%, at least 70%, atleast 80%, or at least 90% carbon dioxide by weight.

In certain non-limiting embodiments, the level of carbon dioxiderecovery from a gaseous or liquified mixture may be at least 40% byweight, at least 50% by weight, at least 60% by weight, at least 70% byweight, at least 80% by weight, at least 90% by weight or at least 95%by weight.

Non-limiting examples of known collection methods include separatingbiogenic carbon dioxide from a gaseous mixture with a liquid absorbentor solid sorbent, membrane separation or separation of carbon dioxidefrom other constituents in liquid form. Carbon dioxide can be separatedfrom impurities in a gas stream using a liquid absorbent, such as asolvent or solid sorbent that is capable of capturing carbon dioxide.After capturing carbon dioxide, the liquid absorbent or solid sorbent isregenerated to release the carbon dioxide. The liquid absorbent or solidsorbent can subsequently be used to capture more carbon dioxide. A solidsorbent includes minerals, zeolites and activated carbon. Membranes arematerials that allow the selective permeation of a gas through them.Membrane materials may be polymeric, metallic or ceramic and theselectivity of the membrane for the gaseous constituents depends onnature of the material of which it is made.

Separation of carbon dioxide from other constituents in liquid form mayinvolve liquifying a gas comprising carbon dioxide by compression,cooling and expansion steps. When in liquid form, the carbon dioxide canbe separated by distillation. Refrigerated systems may also be used forcarbon dioxide separation.

A number of specific techniques for obtaining carbon dioxide fromvarious gaseous streams resulting from fermentation, gasification,pyrolysis or combustion are described below. However, it will beunderstood that the invention is not restricted in scope to the methodsdescribed above and encompasses alternative or additional procedures forrecovering biogenic carbon dioxide, as would be known in the art.

Known techniques for collecting carbon dioxide from fermentationsinclude the use of liquid absorbents. For example carbon dioxide can berecovered using a scrubbing unit in which water is flowedcounter-current to the carbon dioxide-containing stream to remove waterand water soluble components, including the fermentation product. Waterthat remains in the carbon dioxide is subsequently removed in acompressor to increase the pressure of the carbon dioxide up to thewater condensation level. The carbon dioxide may be fed to a drying unitto remove additional water. A purifying unit, which typically containsactivated carbon, may be included in the process configuration before orafter the drying unit to remove impurities. Inert gases, such as oxygenand nitrogen (also referred to in the art as non-condensable orpermanent gases), may subsequently be removed in a condenser.

Carbon dioxide can be recovered from crude syngas produced fromgasification or from a stream resulting from reacting the carbonmonoxide with steam in a water gas shift reaction to produce a streamcomprising carbon dioxide and hydrogen. Further, the biogenic carbondioxide may be collected from excess carbon dioxide generated during thegasification or collected from a recycle stream, such as, withoutlimitation, a carbon dioxide stream recycled during syngas fermentation.

Without being limiting, the carbon dioxide can be separated by physicalor chemical absorption to produce a carbon dioxide-containing stream.The physical absorption may involve the use of membranes that allow theselective permeation of a gas through them. For example, the carbondioxide can be recovered by membranes that are more permeable to carbondioxide than other components in the carbon dioxide-containing stream.The carbon dioxide passes through the membrane while other components donot, thereby resulting in a stream that is carbon dioxide enriched. Thecarbon dioxide-enriched stream can be used in gas or liquid form.Chemical absorption involves the use of chemical solvents. Examples ofchemical solvents include methanol, N-methyl-2-pyrolidone, dimethylethers of polyethylene glycol, potassium carbonate, monoethanolamine,methyldiethylamine and tetrahydrothiophene 1,1-dioxide. A known methodfor recovering carbon dioxide from a stream comprising carbon dioxideand hydrogen resulting from a water gas shift reaction is a Rectisol®wash process that uses methanol as a solvent. Amine gas scrubbing isanother example of a technique involving chemical absorption. Aprevalent amine for such applications in monethanolamine.

Carbon dioxide can be obtained from a gaseous stream, such as a flue gasstream produced from a combustion process that uses the non-fossilorganic material as a feed. This includes combustion of organic materialin a power plant, such as a plant that otherwise burns fossil fuel suchas natural gas or coal. Such a combustion includes an oxyfuel combustionprocess.

Gaseous streams from combustion contain carbon dioxide and otherimpurities depending on the source. Carbon dioxide can be separated fromimpurities in the gas stream using a liquid absorbent or solid sorbentthat is capable of capturing carbon dioxide. The liquid absorbent may bea chemical solvent, such as an amine, or a Selexol™ solvent which usespolyethylene glycol as a solvent. The liquid absorbent can be added aspart of a scrubbing operation, such as amine scrubbing. Regeneration ofthe chemical solvent may then be conducted by stripping or otherseparation techniques, with the regenerated chemical solvent being usedto capture more carbon dioxide. A solid sorbent may include a zeolite oractivated carbon. For solid sorbents, regeneration may be achieved by achange in pressure or temperature, thereby releasing the carbon dioxideand regenerating the sorbent for further use.

Biogenic carbon dioxide from oxyfuel combustion can be separated fromother gaseous components by distillation. A carbon dioxide-containingstream can be liquefied by compression, cooling and expansion steps. Thecarbon dioxide can subsequently be separated in liquid form in adistillation column. A further example of a technique for carbon dioxideseparation from other components is refrigerated separation.Distillation or refrigerated separation can also be used to separatecarbon dioxide from synthesis gas that has undergone a water-gas shiftconversion of carbon monoxide to carbon dioxide.

The biogenic carbon dioxide may be collected from two separate steps ofa process to convert the organic material to a fuel, fuel intermediateor energy product. To illustrate, carbon dioxide may be collected from afermentation of organic material to produce a liquid fuel, such as analcohol. In addition, carbon dioxide may be recovered from an anaerobicdigestion or gasification of a waste stream generated from such liquidfuel fermentation. By collecting carbon dioxide from two or more stepsof the same or different processes, the yield of the fuel, fuelintermediate, chemical product or energy product from the organicmaterial can be further increased.

Forming the Biogenic Carbon-Based Fuel or Fuel Intermediate

As discussed, by collecting biogenic carbon dioxide obtained or derivedfrom a process that produces a fuel, a fuel intermediate, a chemicalproduct or an energy product, and subsequently using the biogenic carbondioxide to produce a second biogenic carbon-based fuel, a greater amountof the carbon of the initial organic material can be converted to afinal product. This in turn can result in significant improvements inbiogenic product yield from the starting material. For example, incertain embodiments of the invention, the total energy of the biogeniccarbon-based fuel or products that can be produced from the non-fossilorganic material can be increased by at least 10%, 25% or 30% relativeto a conventional biofuel production process without collecting carbondioxide.

The biogenic carbon dioxide can be reduced using fossil derived hydrogento other C₁-C_(n) molecules in one or more chemical and/or biologicconversions. Representative examples of such processes are describedbelow.

The fossil derived hydrogen is sourced from a process that producesfossil-containing molecules, such as carbon monoxide and/or carbondioxide, and hydrogen from a fossil fuel hydrocarbon. In such process,the fossil-containing molecules are separated from the hydrogen.Preferably, all the carbon-containing molecules are removed, typicallyto achieve more than 90% or 95% by weight hydrogen. The hydrogen thusobtained is typically a low cost source compared to other sources, suchas renewable sources. This hydrogen is then used in the production ofthe second biogenic-based fuel or fuel intermediate. While hydrogen fromfossil fuel is used in the biofuel production, since the hydrogen doesnot itself contain fossil carbon the carbon dioxide tailpipe emissionsthat result from combustion of the biofuel, such as in transportationvehicles, contain only biogenic carbon, and thus are considered to havea neutral effect on atmospheric carbon dioxide levels. Although thecarbon dioxide emissions associated with the hydrogen production fromfossil fuels are included in the GHG emission analysis, by practicingembodiments of the invention, the life cycle GHG emissions of the fuelor fuels produced can be reduced relative to a gasoline baseline, whileat the same time using a low cost hydrogen source.

In certain embodiments of the invention, the amount of biogenic carbonin the second biogenic carbon-based fuel or fuel intermediate may bebetween 70 mole % and 100 mole % (mol:mol), between 75 mole % and 100mole %, between 80 mole % and 100 mole %, between 85 mole % and 100 mole%, between 90 mole % and 100 mole % or between 95 mole % and 100 mole %(mol:mol of biogenic and non-biogenic carbon).

In an embodiment of the invention, radiocarbon analysis can be used todetermine the presence of a biogenic component in the biogeniccarbon-based fuel or fuel intermediate using known methodology forcarbon 14 dating. However, it should be understood that the carboncomponent of the biogenic fuel or fuel intermediate may be non-biogenic,but still be recognized as biogenic. To illustrate, if the fuel isderived from carbon dioxide withdrawn from a pipeline, and such carbondioxide is non-biogenic, or a contains a mixture of biogenic andnon-biogenic carbon dioxide and yet qualifies as renewable underprevailing regulations, the withdrawn carbon dioxide will still beconsidered biogenic.

Sourcing the hydrogen includes directly or indirectly obtaining hydrogenfor use in the production of the fuel or fuel intermediate, includingobtaining the hydrogen from a third party. If the hydrogen is sourcedfrom a third party, it may be obtained directly or indirectly by way ofwritten documentation, including a contract, or other agreement betweentwo or more parties.

The stream sourced from the hydrogen production process is referred toas a “stream enriched in hydrogen”, meaning a stream comprising greaterthan 80 mol % hydrogen (mol:mol).

The fossil derived hydrogen may be produced by a process in whichmethane is converted to a syngas stream comprising carbon monoxide andhydrogen. Subsequently, further hydrogen enrichment steps may beconducted on the syngas stream or a stream derived therefrom to producea stream with increased hydrogen content relative to syngas. Thehydrogen may be enriched by various techniques known to those of skillin the art including by membranes, adsorbents or by further chemicalconversions conducted to produce additional hydrogen.

In certain non-limiting embodiments of the invention, the hydrogen issourced from reforming, such as steam methane reforming (SMR) orautothermal reforming (ATR). Both steam methane reforming andauthothermal reforming methods operate by exposing the methane to acatalyst at high temperature and pressure to produce syngas, which is amixture comprising hydrogen and carbon monoxide. Steam methane reformingis often referred to as a non-oxidative process that converts themethane into hydrogen and carbon monoxide by the following reaction:CH₄+H₂O→CO+3H₂

Autothermal reforming uses oxygen and carbon dioxide or oxygen and steamin a reaction with methane to form carbon monoxide and hydrogen. Theauthothermal reaction using oxygen and carbon dioxide can be describedby the following reaction:2CH₄+O₂+CO₂→3H₂+3CO+H₂O.The autothermal reaction using oxygen and steam proceeds by thefollowing reaction:4CH₄+O₂+2H₂O→10H₂+4CO.

Examples of other reforming reactions include partial oxidation and dryreforming.

The reforming may be followed by a water gas shift reaction to producethe fossil carbon dioxide and hydrogen. For example, steam methanereforming followed by a water gas shift converts natural gas to carbondioxide and hydrogen as follows:CH₄+H₂O→CO+3H₂CO+H₂O→CO₂+H₂Overall: CH₄+2H₂O→CO₂+4H₂

In one embodiment of the invention, the water gas shift includes atleast a high temperature shift, which is a water gas shift typicallyconducted at a temperature of at least 275° C., typically higher than300° C. An example of a temperature range for the high temperature shiftis 300° C. to 450° C. Subsequent to a high temperature shift, a lowtemperature shift is optionally conducted. The low temperature shiftoccurs at a lower temperature than a high temperature shift, such as atemperature lower than 300° C., more typically less than 250° C. Anexample of a temperature range for the low temperature shift is 180° C.to 250° C. The high temperature shift generally results in theincomplete conversion of carbon monoxide to carbon dioxide. A lowtemperature shift may increase such conversion, thereby reducing thecarbon monoxide concentration further. This may produce an outlet streamhaving a carbon monoxide mole % of less than 5 mol %, less than 3 mol %,more typically less than 2 mol %. Both high and low temperature shiftreactions are generally carried out in the presence of a catalyst.

The stream resulting from the reforming and the water gas shift reactiontypically contains a relatively high concentration of hydrogen andcarbon dioxide, making this gaseous component more easily recoverablerelative to waste streams generated from other processes that burnfossil fuel, such as flue gases from power plants. The fossil carbondioxide recovered can then be introduced underground in a geologicformation, thereby further reducing GHG emissions associated with thebiogenic fuel or fuel intermediate. Another advantage of using hydrogenfrom steam methane or authothermal reforming is that, in some regions,natural gas can be obtained at low cost relative to renewable options.As a result, the use of natural gas to make hydrogen, with theintroduction of the low energy content carbon dioxide byproductunderground, provides not only an economical source of high energyhydrogen for the process, but also GHG benefits that can be attained atminimal cost.

The hydrogen produced by the water gas shift reaction can be recoveredfrom non-hydrogen components, including carbon dioxide, from a gaseousor liquid stream using known techniques employing adsorbents ormembranes. An example of a recovery technique using adsorbents ispressure swing adsorption (PSA), which is commonly used to recoverhydrogen produced by steam methane reforming. As would be appreciated bythose of skill in the art, PSA is used to separate gas species from amixture of gases under pressure using adsorbent materials such aszeolites, molecular sieves or activated carbon. The adsorbent materialabsorbs the target gas species at high pressure and the separationrelies on the different affinity of various gas species in the gasstream. When the pressure is lowered, the target gas desorbs. In thepractice of certain embodiments of the present invention, PSA adsorbshydrogen and the desorption results in a stream concentrated inhydrogen. A stream comprising non-adsorbed species, including carbondioxide, is also generated by PSA. This latter stream comprising carbondioxide is often referred to as a purge gas stream.

As noted, carbon dioxide for introduction underground can be recoveredfrom one or more streams comprising carbon dioxide generated during theabove-mentioned hydrogen production process. FIG. 5 is a process flowdiagram depicting non-limiting examples of streams produced during thehydrogen production process from which carbon dioxide can be recovered.As shown, the hydrogen production process uses fossil methane as a feed,which is subjected to steam reforming unit 50, followed by a water gasshift reaction 70 and a PSA unit 90. The PSA unit 90 produces a streamenriched in fossil hydrogen, in this case at levels greater than 99 mol% hydrogen and a tail gas stream 180 comprising carbon dioxide, carbonmonoxide and hydrogen. The fossil carbon dioxide can be recovered fromthis tail gas stream 180 in CO₂ recovery unit 190. A further example ofa stream from which carbon dioxide can be recovered is a stream exitinga water gas shift unit and upstream of the pressure swing adsorptionunit 90 in recovery unit 200. Moreover, carbon dioxide can also berecovered from any process unit upstream of a water gas shift reaction.An example of such a stream is a flue gas stream 210 exiting a steammethane reforming unit 50 in which the steam methane reforming reactionis conducted. The carbon dioxide can be recovered from this stream 210in carbon dioxide recovery 220. The carbon dioxide can be recovered fromthis stream 210 in carbon dioxide recovery 220. This latter stream isproduced upon combustion of fuel gas, such as methane, hydrogen and/orcarbon monoxide used for supplying heat to steam methane reforming unit50. The combustion of these components to supply heat results in theproduction of fossil carbon dioxide that is often otherwise vented.Recovery of fossil carbon dioxide from any of these streams can becarried out using known techniques, including processes usingadsorbents, membranes, solvents or other suitable techniques known tothose of skill in the art.

As mentioned, the biogenic carbon dioxide and fossil derived hydrogenare used to form the biogenic carbon-based fuel or fuel intermediate bya variety of different single and/or multi-step chemical or biologicproduction processes. Examples of production processes are set forthbelow.

(a) Production Processes Using Hydrogen and Carbon Dioxide to ProduceCarbon Monoxide

The biogenic carbon dioxide and hydrogen sourced from fossil fuel may beused to produce carbon monoxide as a feedstock for biofuel production bythe following reverse water gas shift reaction:CO₂+H₂→CO+H₂O

The carbon monoxide produced by the above reaction can be furtherconverted in one or more chemical and/or biological steps to a fuel orfuel intermediate. For example, combining carbon monoxide from the abovereaction with hydrogen results in syngas that can be used itself as afuel or to produce a fuel or fuel intermediate. As described previously,examples of products made directly or indirectly from syngas includeliquid hydrocarbons, methane, hydrogen, methanol, ethanol or ammonia.

The above reverse water gas shift reaction to produce carbon monoxidecan be conducted as part of a reforming operation. According to suchembodiment, the biogenic carbon dioxide and fossil derived hydrogen maybe fed to a reformer. The steam reforming may be operated such that theforegoing reverse water gas shift occurs during the steam reforming,thereby producing carbon monoxide and water. The output from the steamreforming will then include syngas comprising carbon monoxide, hydrogenand carbon dioxide. The resultant syngas can subsequently be convertedto products via one or more biologic and/or chemical conversions. In oneembodiment of this aspect of the invention, the syngas is converted to ahydrocarbon through a chemical conversion, such as the Fischer-Tropschreaction described earlier or alternatively a process in which thesyngas is converted to methanol and then to the hydrocarbon, such asgasoline, described in more detail hereinafter. In either case, theproduct from the syngas will contain biogenic carbon.

The steam reformer may be fed with a stream comprising biogenic carbondioxide and methane derived from anaerobic digestion, along with fossilderived hydrogen. The presence of methane can aid in reducing the fossilhydrogen requirement because hydrogen is produced in situ from methanein the reformer.

A non-limiting example of a process in which biogenic carbon dioxide andfossil derived hydrogen are fed to a reformer to produce syngas, whichin turn is converted to a hydrocarbon fuel or fuel intermediate that cansubstitute gasoline, diesel or other petroleum products is provided inFIG. 4, as described in more detail in Example 4.

The reforming to produce syngas from biogenic carbon dioxide andhydrogen and the steam methane reforming and/or a water gas shift toproduce hydrogen from fossil methane often generates excess heat. Theheat generated from any one or a combination of these reforming andwater gas shift operations can be used to provide energy in other unitoperations. For example, the heat can be used to supply energy in aprocess to produce an energy product or a chemical product, a fuel or afuel intermediate from the non-fossil organic material. The process caninclude the fermentation of non-fossil organic material to produceethanol. For example, such heat can be utilized in a dryer, thermaloxidizer, distillation and/or evaporation in an ethanol productionprocess using corn as a feedstock. Alternatively, the heat can be usedin a production process to make ethanol from biomass or biomass derivedmaterial. This includes supplying heat to similar operations as a cornethanol process or for pretreatment processes. In a further embodimentof the invention, heat from the reforming can be used to supply energyfor a production process in which syngas is converted to a hydrocarbonthrough a chemical conversion such as that described above. In anotherembodiment of the invention, heat from the reforming can be used toproduce electricity either for internal use or for export to the grid.By implementing such energy savings, the life cycle GHG emissions can bereduced by at least 20% relative to a gasoline baseline. Advantageously,such GHG savings can enable the generation of a biofuel credit inrelation to the fuel produced or sold.

Syngas produced by the reverse water gas shift can also be converted toa fuel, fuel intermediate and/or chemical product by a biologicconversion utilizing microorganisms or other biocatalysts. For example,acetogenic microorganisms can be used to produce a biogenic carbon-basedproduct from carbon monoxide through fermentation. For example,anaerobic microorganisms from the genus Clostridium can produce ethanolor other products from the carbon monoxide.

The production of ethanol by the acetogenic microorganisms proceedsthrough a series of biochemical reactions. Without being bound by anyparticular theory, the reactions carried out by the microorganism are asfollows:6CO+3H₂O→CH₃CH₂OH+4CO₂6H₂+2CO₂→CH₃CH₂OH+3H₂O

Examples of strains that can produce ethanol from syngas are those fromthe genus Clostridium. In addition to ethanol, Clostridium bacteriamight produce significant amounts of acetic acid (or acetate, dependingon the pH) in addition to ethanol, although to improve ethanol yield itis possible to adjust fermentation conditions by nutrient limitation orby providing excess fossil derived hydrogen or carbon monoxide toachieve a desired ethanol productivity. Such conditions can be readilyselected by those of skill in the art and it should be appreciated thatthe invention is not constrained by any particular set of parametersselected for fermentation to improve productivity.

The carbon monoxide from the above reverse water gas shift reaction canalso be reacted with fossil derived hydrogen to produce methanol. Thereactions are as follows:CO₂+H₂→CO+H₂O (reverse water gas shift)CO+2H₂→CH₃OH

Another route for producing methanol is the direct hydrogenation of CO₂to produce methanol (not shown).

In a further embodiment, the methanol is used as a fuel intermediate tomake another fuel. Ethanol is one such fuel and its production frommethanol can proceed by a variety of different reaction routes. Theproduction of ethanol from methanol through organic acid intermediates,such as acetic acid, is known in the art. For example, methanol can bereacted with carbon monoxide to make acetic acid, acetate or acombination thereof, and the acetate is subsequently reacted withhydrogen to make ethanol and water. The reaction is as follows:CH₃OH+CO→CH₃COOHCH₃COOH+2H₂→CH₃CH₂OH+H₂O

The hydrogenation of acetic acid may favour the production of ethylacetate over ethanol. Special hydrogenating catalysts (platinum/copperor palladium/cobalt) may be used to produce ethyl acetate from aceticacid. The ethyl acetate can then be hydrogenated to ethanol. Ethanolproduction can also proceed via a methyl acetate intermediate. Accordingto such embodiment, methanol is carbonylated to methyl acetate andoptionally acetic acid. The methyl acetate is then hydrogenated toethanol.

The methanol can also be converted to gasoline by forming dimethyl etherby a dehydration reaction. Subsequently, an equilibrium mixture ofmethanol, dimethylether and water is converted to short-chain olefins.In a further reaction step, the short-chain olefins are reacted to formhigher olefins, including n/iso-paraffins, aromatics and napththenes,which are further treated to make gasoline.

(b) Other Processes Employing Conversion of Biogenic CO₂ and FossilDerived H₂ to Products

The biogenic CO₂ and fossil derived H₂ can also be more directlyconverted to the biogenic carbon-based fuel or fuel intermediate ratherthan proceeding through a reverse water gas shift reaction to produce COand H₂O. Representative examples of such processes are described below.

According to one embodiment of the invention, the biogenic carbondioxide and fossil derived hydrogen is converted to an alcohol, such asethanol, by fermentation with a bacterium. In such embodiment, ethanolis produced from CO₂ and H₂ by the following reaction scheme:6H₂+2CO₂→CH₃CH₂OH+3H₂O

The ethanol produced is referred to as “biogenic ethanol”, meaning thatcarbon in the ethanol is from biogenic carbon or considered renewable orbiogenic by those of skill in the art.

By adding fossil derived hydrogen in accordance with the invention, theabove reaction can provide for significant yield increases relative toconventional ethanol production processes. In certain embodiments, theyield of ethanol achieved by the invention can be greater than 10%, 20%or 30% relative to the yield from conventional processes for producingbiogenic ethanol from corn without collecting biogenic carbon dioxideand using it to make a product. Moreover, a byproduct generallyconsidered a low energy waste product from processing of biomass orbiomass-derived material can be converted into a valuable biofuel, inparticular a biofuel that is eligible for fuel credit generation byvirtue of its biogenic carbon. Further, using fossil derived hydrogen isuniquely low cost compared to other potential sources of hydrogen. Thus,in certain advantageous embodiments, a higher yield of biofuel may beachieved by a low cost method.

The production of ethanol from fossil derived hydrogen and biogeniccarbon dioxide may be carried out with hydrogen oxidizingchemoautotrophs. Microorganisms useful in the practice of the inventionmay include any bacteria from a genus selected from Acetogenium,Acetobacterium, Acetoanaerobium, Butyribacterium and Clostridium thatare capable of the above bioconversion. In one embodiment of theinvention, the microorganism used to produce ethanol is from the genusClostridium. Without being limiting, a particularly suitablemicroorganism for producing ethanol from the biogenic carbon dioxide andfossil derived hydrogen is Clostridium ljungdahlii. This bacterium caneffectively convert biogenic carbon dioxide and hydrogen to ethanol.

A representative example of a process in which biogenic carbon dioxideand hydrogen from fossil fuel are fermented to produce ethanol isprovided in FIG. 1, and described in more detail in Example 1 below.

The fossil derived hydrogen is typically provided in excess of biogeniccarbon dioxide to satisfy the above stoichiometric molar ratio of H₂:CO₂of 3:1 to produce ethanol according to the foregoing reaction scheme. Anexample of a range of molar ratios of H₂:CO₂ that can be utilized in thepractice of the invention is from 2:1 to 4:1 or from 2.5:1 to 3.5:1. Thegases, hydrogen and carbon dioxide, are introduced to the bioreactoreither together in a combined stream comprising both components or asseparate respective streams. This includes the introduction of the gasestogether or separately along with broth. The bioreactor contains aliquid nutrient broth containing the bacteria and components requiredfor their growth, such as vitamins and salts. In one embodiment of theinvention, the bioreactor is one of a plurality of bioreactors in asystem in which the reactors are arranged in series, parallel or acombination of such arrangements. A growth reactor may also be utilizedwhich feeds a separate bioreactor in which most of the product ethanolis produced or a growth phase can be carried out in a fermentationbioreactor itself.

The bioreactor for conducting the conversion can be a stirred or anunmixed tank reactor. An example of a bioreactor that can be used toferment the fossil derived hydrogen and biogenic carbon dioxide is adeep tank bioreactor, which is a reactor generally having a depth ofgreater than 10 meters. The deep tank reactor may be stirred tofacilitate contact between the gases and the liquid nutrient broth. Thegases may also be introduced at the bottom region of the bioreactor andbubble through the liquid broth. Optionally, the gases are introducedalong with the liquid broth, such as together with a brothre-circulation stream. Mechanical pumping may also be utilized tofacilitate liquid flow and mass transfer. Another type of reactor thatcan be utilized in the practice of the invention is a gas lift reactor,wherein the broth is agitated through the use of gas nozzles.

The bioreactor may employ cell recycle in order to replenish theconcentration of cells in the reactor. According to such embodiment, aliquid stream comprising cells is withdrawn from the reactor and sent toa solids-liquid separation to separate cells from the stream. Theseparated cells are returned to the reactor and a cell-free streamresulting from the separation is sent to product recovery to recoverethanol, typically by distillation.

Gases may accumulate in the headspace of the reactor. Such gases may berecycled back to the bioreactor or can be fed back to an SMR either asfeedstock or as fuel. The gases withdrawn from the reactor may becombined with a stream comprising carbon dioxide and hydrogen introducedto the reactor.

The recovery of ethanol can be carried out using conventionaltechniques, such as distillation followed by further concentration bymolecular sieves. After recovery of ethanol, a stream remains referredto as still bottoms. The still bottoms stream can be sent to asolids-liquid separation and the liquid stream resulting from theseparation can be fed back to the reactor. Still bottoms fromdistillation or a fraction thereof may also be sent to an evaporatorunit. In such unit, the still bottoms are concentrated and theevaporated liquid is condensed by cooling. The evaporator condensate maythen be recycled as a liquid stream back to the reactor to reduce waterusage.

Alternatively or in addition to water recycle, at least a portion of theliquid stream obtained from the still bottoms can be fed to an anaerobicdigestion. The anaerobic digestion produces a stream comprising methaneand carbon dioxide. The carbon dioxide can be separated from othercomponents of the biogas and introduced to the bioreactor in whichcarbon dioxide and hydrogen are converted to ethanol.

While the production of ethanol from carbon dioxide and hydrogen hasbeen described, hydrogen oxidizing chemoautotrophs can also produceacetic acid from these gaseous substrates. For example, Clostridiumspecies are known to produce acetic acid by the following reactionmechanism:4H₂+2CO₂→CH₃COOH+2H₂O

As would be appreciated by those of skill in the art, acetic acid,acetate or both of these species will be present as dictated by the pHof the solution.

Acetic acid can be sold as a product in either the acetate or acid formor converted to a fuel such as ethanol. Acetic acid can also beintroduced back to an anaerobic digester and converted to methane byanaerobic digestion.

Products that are gaseous at standard temperatures and pressures canalso be produced from biogenic carbon dioxide and fossil derivedhydrogen. According to further embodiments of the invention, thebiogenic carbon dioxide and fossil derived hydrogen can be used toproduce methane via the following reaction:CO₂+4H₂→CH₄+2H₂O

The foregoing mechanism for producing methane is referred to herein as a“methanation” or “Sabatier reaction”. The methane thus produced can beused itself as fuel or can be used as a fuel intermediate to produceanother fuel or fuel intermediate, as set out previously. The abovereaction can be carried out as either a biologic or chemical conversion.

In certain embodiments of the invention, the formation of methane usingbiogenic carbon dioxide and fossil derived hydrogen can be carried outas part of a process to improve methane yield from a process thatproduces methane from non-fossil organic material, such as anaerobicdigestion. As described above, anaerobic digestion produces methane andother components including biogenic carbon dioxide. The biogenic carbondioxide and methane can be separated from crude biogas and combined withthe hydrogen sourced from fossil fuel hydrocarbon or methane and carbondioxide can be processed together with hydrogen to make methane orsyngas. The biogenic carbon dioxide is converted to methane by reactionwith hydrogen according to the above reaction.

The methanation reaction with fossil derived hydrogen thus producesadditional methane from the biogenic carbon dioxide generated duringanaerobic digestion. The foregoing process results in a higher yield ofbiogenic carbon-based fuel or fuel intermediate from the originalnon-fossil organic material. The product is considered a biofuel.

Although the methanation reaction is described above in connection withimproving methane yield, it should be understood that the biogeniccarbon dioxide may be obtained from any fermentation of non-fossilorganic material or alternatively from a thermal process.

The methanation reaction may take place in a reactor in the presence ofa catalyst, typically a metal. The methanation reaction can also becarried out as a biologic conversion. For example methanogenic,hydrogen-utilizing microbes including Methanobacteriales,Methanococcales, and Methanomicrobiales or Methanopyrales can producemethane from carbon dioxide and hydrogen. Such microorganisms are knownas hydrogenotrophic methanogens.

According to another embodiment, the biogenic carbon dioxide is reactedwith a hydrocarbon, such as methane. According to this embodiment, thehydrocarbon comprises at least one hydrogen atom that originates fromthe fossil derived hydrogen. For example, methane can be reacted withbiogenic carbon dioxide to produce syngas in a dry reforming process.The syngas can subsequently be reacted to make methanol. The reactionsare as follows:CH₄+CO₂→H₂+2COCO+2H₂→CH₃OHReducing GHG Emissions

Embodiments of the process of the present invention may comprisecarrying out or arranging for one or more parties to carry out at leastone step that contributes to a reduction in the life cycle GHG emissionsof one or more biogenic carbon-based fuels produced directly orindirectly by the process. In certain embodiments, the life cycle GHGemissions can be at least 20%, 30%, 40%, 50%, 60%, 70% or 80% less thana gasoline baseline. Such reductions in life cycle GHG emissions canallow for advantaged fuel credit generation, as discussed below.

As used herein “arranging” or “causing” means to bring about, eitherdirectly or indirectly, or to play a required role in a series ofactivities through commercial arrangements such as a written agreement,verbal agreement or contract.

The at least one step for reducing GHG emissions may compriseintroducing fossil carbon dioxide underground that is generated duringthe production of hydrogen from fossil fuel hydrocarbon. For example,the fossil carbon dioxide may be introduced into an undergroundgeological formation, thereby reducing life cycle GHG emissions bypreventing carbon from fossil sources from being emitted to theatmosphere. Without being limiting, the fossil carbon dioxide may beintroduced underground for extracting oil or gas in an enhanced oil orgas recovery. A description of enhanced oil and gas recovery is setforth in U.S. Patent Publication No. 2013/0089905 (published Apr. 11,2013), which is incorporated herein by reference and particularly forthe purpose of describing enhanced oil and gas recovery. The enhancedoil or gas recovery is any process that enables the recovery ofunderground oil or gas with the aid of fluid, including liquid or gasinjection or two-phase fluid, such as foam. Carbon dioxide can also beinjected into saline aquifers or other geologic formations in which thecarbon dioxide can be contained, although as would be appreciated bythose of skill in the art, some amount of carbon dioxide leakage mayoccur from the formation over a relatively long period of time. Inanother embodiment, the at least one step for reducing GHG emissions maycomprise incorporating the fossil carbon dioxide into manufacturedchemical products such as sodium bicarbonate and/or calcium carbonatethat are stable and thus greatly slow or substantially prevents thefossil carbon dioxide from being emitted into the atmosphere.

In order to transport the fossil carbon dioxide to the proximity of anunderground geologic formation, it may be introduced to an apparatus fortransporting carbon dioxide, such as a pipeline, railroad car or truck.An amount of carbon dioxide is withdrawn from the transport apparatusfor introduction underground, typically by a different party than theparty that generates the carbon dioxide. In this case, the party thatproduces the fossil derived hydrogen and the fossil carbon dioxide mayarrange for, or cause, a third party to withdraw an amount generallycorresponding to that introduced to the transport apparatus (e.g.,pipeline).

According to a further embodiment of the invention, the first chemicalor energy product produced or derived from the non-fossil organicmaterial displaces a chemical or energy product made from fossil fuel.By displace, it is meant that the first energy product or chemicalproduct, reduces or is recognized by those skilled in the art asreducing, the production or use of a corresponding fossil derived energyor chemical product, thereby reducing the life cycle GHG emissionsassociated with the biofuel. The GHG emission reductions are typicallyreflected in a life cycle GHG emission calculation. The GHG emissionsfor production or use of the chemical or energy product are therebyreduced because the GHG emissions associated with the displaced chemicalor energy product from fossil fuel are avoided, and replaced with achemical or energy product produced or derived from non-fossil organicmaterial. The chemical or energy product produced from fossil fuelenergy sources is referred to as a fossil derived chemical or energyproduct.

Fossil derived hydrogen can also be transferred by a transportapparatus, such as a pipeline, railroad car or truck. In someembodiments, collection of carbon dioxide from the hydrogen productionprocess reduces the GHG emissions attributable to hydrogen and suchbeneficial environmental attributes may be transferred by feeding suchhydrogen into a transport apparatus and withdrawing an equivalent amountfrom the transport apparatus, thus transferring the environmentalattributes to the withdrawn hydrogen.

By way of example, the electricity produced by combusting biomass orbiomass derived material, such as lignin, may displace the production oruse of fossil derived electricity from a coal burning power plant.Displacement of an energy product generally involves exporting theenergy product from the process. In a further example, a chemicalproduct such as acetic acid produced from methanol derived fromnon-fossil organic material can displace acetic acid made from fossilsources.

Determining Life Cycle GHG Emissions

As mentioned, according to certain embodiments of the invention, one ormore biogenic carbon-based fuel that is produced in the process, whichincludes by downstream parties, has life cycle GHG emissions associatedtherewith that are at least 20%, 30% or 40% lower than a gasolinebaseline. However, in certain embodiments, these savings can be at leastas much as 50% lower than a gasoline baseline, or even at least as muchas 60%, 70%, 80% or 90% lower than a gasoline baseline.

To determine life cycle GHG emissions associated with a biogeniccarbon-based fuel, analyses are conducted to calculate the GHG emissionsrelated to the production and use of the fuel throughout its life cycle.Life cycle GHG emissions include the aggregate quantity of GHG emissionsrelated to the full life cycle of the transportation or heating fuel,including all stages of fuel and feedstock production and distribution,from feedstock generation or extraction through the distribution anddelivery and use of the finished fuel to the ultimate consumer. GHGemissions account for total net GHG emissions, both direct and indirect,associated with feedstock production and distribution, the fuelproduction and distribution and use.

Examples of Methodologies for Calculating Life Cycle GHG Emissions

Because many of the laws adopted differentiate the requirements forfuels based upon their net GHG emissions impacts, those skilled in theart are familiar with methods to analyze and characterize the expectednet GHG emissions of fuel pathways that regulators have developed and/oradopted. Thus, life cycle GHG emissions are determined in accordancewith such methods known to those skilled in the art, in accordance withprevailing rules and regulations.

Life cycle GHG emissions evaluations generally consider GHG emissionsassociated with each of:

-   (a) feedstock production and recovery, including the source of    carbon in the feedstock, direct impacts such as chemical inputs,    energy inputs, and emissions from the collection and recovery    operations, and indirect impacts such as the impact of land use    changes from incremental feedstock production;-   (b) feedstock transport, including feedstock production and recovery    and GHG emissions from feedstock transport including energy inputs    and emissions from transport;-   (c) fuel production, including chemical and energy inputs, emissions    and byproducts from fuel production (including direct and indirect    impacts); and-   (d) transport and storage of the fuel prior to use as a    transportation or heating fuel, including chemical and energy inputs    and emissions from transport and storage.

Known models to measure life cycle GHG emissions associated with the oneor more fuels of the invention, include, but are not limited to:

-   GREET Model—GHGs, Regulated Emissions, and Energy Use in    Transportation, the spread-sheet analysis tool developed by Argonne    National Laboratories;-   (ii) FASOM Model—a partial equilibrium economic model of the U.S.    forest and agricultural sectors developed by Texas A&M University;-   (iii) FAPRI International Model—a worldwide agricultural sector    economic model that was run by the Center for Agricultural and Rural    Development (“CARD”) at Iowa State University;-   (iv) GTAP Model—the Global Trade Analysis Project model, a    multi-region, multi-sector computable general equilibrium model that    estimates changes in world agricultural production as well as    multiple additional models; and-   (v) ISO (International Organization for Standardization) standards    for GHG emissions accounting and verification—provides guidance for    quantification, monitoring and reporting of activities intended to    cause greenhouse gas (GHG) emission reductions or removal    enhancements.

The life cycle GHG emissions or carbon intensity of the biogeniccarbon-based fuel is generally measured in carbon dioxide equivalents(CO₂eq). As would be understood by those of skill in the art, carbondioxide equivalents are used to compare the emissions from various GHGsbased upon their global warming potential (GWP), which is a conversionfactor that varies depending on the gas. The carbon dioxide equivalentfor a gas is derived by multiplying the amount of the gas by theassociated GWP.grams of CO₂ eq=((grams of a gas)*(GWP of the gas))

The GWP conversion value used to determine grams of CO₂eq will depend onapplicable regulations for calculating life cycle GHG emissionsreductions. The GWP under EISA is 1, 21 and 310, respectively, forcarbon dioxide, methane and nitrous oxide as set forth in Renewable FuelStandard Program (RFS2) Regulatory Impact Analysis, February 2010,United States Environmental Protection Agency, EPA-420-R-10-006, pg. 13,of which the entire contents are incorporated herein by reference. UnderCalifornia's LCFS, the GWP is 1, 25 and 298, respectively, for carbondioxide, methane and nitrous oxide, as measured by the GREET model. Itshould be appreciated that GWP values can be readily calculated by thoseof skill in the art in accordance with regulations.

The unit of measure for carbon intensity or life cycle GHG emissionsthat may be used to quantify GHG emissions of the biogenic carbon-basedfuel of the present invention is grams CO₂eq per MJ of energy in thefuel or grams CO₂eq per million British thermal units of energy in thefuel (MNBTU). The units used to measure life cycle GHG emissions willgenerally depend on applicable regulations. For example, under the EPAregulations, GHG emissions are measured in units of grams CO₂eq permillion BTUs (MMBTU) of energy in the fuel. Under LCFS, GHG emissionsare measured in units of grams CO₂eq per MJ of energy in the fuel andare referred to as carbon intensity or CI.

The life cycle GHG emissions of the biogenic carbon-based fuel of theinvention are compared to the life cycle GHG emissions for gasoline,referred to as a gasoline baseline. GHG life cycle emissions arecompared by reference to the use of gasoline per unit of fuel energy.

The EPA value for the gasoline baseline used in life cycle GHG emissioncalculations is 98,204 g CO₂eq/MMBTU or 93.10 g CO₂eq/MJ. UnderCalifornia's LCFS, the gasoline baseline is 95.86 g CO₂eq/MJ. Those ofordinary skill in the art can readily convert values herein from gCO₂eq/MJ to g CO₂eq/MMBTU or g CO₂eq/MMBTU to g CO₂eq/MJ by using anappropriate conversion factor.

The life cycle GHG emission reduction relative to a gasoline baseline iscalculated using “EPA methodology”, which means determining life cycleGHG emissions reductions by known methods as disclosed inEPA-420-R-10-006, “Renewable Fuel Standard Program (RFS2) RegulatoryImpact Analysis”, February 2010, which is incorporated herein byreference. In addition, for situations in which fossil carbon dioxide isintroduced underground, such determination of life cycle GHG emissionreduction includes a GHG saving that corresponds to the amount of carbondioxide introduced underground. For example, one tonne of fossil carbondioxide introduced underground would be counted as one tonne GHG savingsin a life cycle GHG emission calculation. As would be appreciated bythose of skill in the art, this method has been used by the EPA toquantify GHG savings due to the introduction of CO2 underground that iscaptured from power plants. (See EPA-HQ-OAR-2013-0495, Jan. 8, 2014).

According to a further embodiment of the invention, the life cycle GHGemission reduction relative to a gasoline baseline can be measured using“LCFS methodology”, which means measuring life cycle GHG emissionsreductions by California's LCFS methodology using the GREET model, asset forth in Detailed California-Modified GREET Pathway for CornEthanol, California Environmental Protection Agency, Air ResourcesBoard, Jan. 20, 2009, Version 2.0.

According to one embodiment of the invention, the life cycle carbondioxide emissions, rather than the life cycle GHG emissions, aredetermined for the biogenic carbon-based fuel and compared to a gasolinebaseline. For example, as would be appreciated by those of skill in theart, when a reduction in carbon dioxide emissions relative to aproduction process baseline is quantified, a life cycle carbon dioxideemission reduction can be quantified instead of a life cycle GHGemission reduction.

Meeting Renewable and Low Carbon Fuel Targets

The invention advantageously provides a methodology for meetingrenewable fuel targets or mandates established by governments, includinglegislation and regulations for transportation or heating fuel sold orintroduced into commerce in the United States. Examples of suchlegislation include the Energy Independence and Security Act (“EISA”)and California AB 32—The Global Warming Solutions Act, whichrespectively established an RFS and a Low Carbon Fuel Standard (LCFS).For example, under EISA, the mandated annual targets of renewablecontent in fuel are implemented through an RFS that uses tradablecredits (called Renewable Identification Numbers, referred to herein as“RINs”) to track and manage the production, distribution and use ofrenewable fuels for transportation or other purposes. Targets under theLCFS can be met by trading of credits generated from the use of fuelswith a lower GHG emission value than the gasoline baseline.

The term “credit”, “renewable fuel credit” or “biofuel credit” means anyrights, credits, revenues, greenhouse gas rights or similar rightsrelated to carbon credits, rights to any greenhouse gas emissionreductions, carbon-related credits or equivalent arising from emissionreduction trading or any quantifiable benefits (including recognition,award or allocation of credits, allowances, permits or other tangiblerights), whether created from or through a governmental authority, aprivate contract or otherwise. According to one embodiment of theinvention, the renewable fuel credit is a certificate, record, serialnumber or guarantee, in any form, including electronic, which evidencesproduction of a quantity of fuel meeting certain life cycle GHG emissionreductions relative to a baseline set by a government authority. Thebaseline is typically a gasoline baseline. Non-limiting examples ofcredits include RINs and LCFS credits in the United States.

The fuel credit may be generated in connection with the biogeniccarbon-based fuel that is used as a transportation or heating fuel.According to an embodiment of the invention, a fuel credit is generatedor caused to be generated with respect to the use of methane or ethanolas a transportation or heating fuel.

In one embodiment, the biogenic carbon-based fuel of the invention couldqualify for an advanced biofuel RIN under EISA having a D code of 3, 4,5 or 7. In a further embodiment, the product of the invention iseligible for a RIN having a D code of 3 or 5. Under the LCFS, productsfor use as fuels with greater reductions in life cycle GHG emissionsqualify for a greater number of credits having higher market value thanfuels with lower reductions.

Energy policy, including EISA and LCFS, and the generation of renewablefuel credits under each of these legislative frameworks, is discussed inturn below.

(a) Meeting Renewable Fuel Targets Under EISA

U.S. policymakers have introduced a combination of policies to supportthe production and consumption of biofuels, one of which includes theRFS. The RFS originated with the Energy Policy Act of 2005 (known asRFS1) and was expanded and extended by the EISA of 2007. The RFSexpanded and extended under EISA is sometimes referred to as RFS2 or RFSas used herein.

Under the EISA, the RFS sets annual mandates for renewable fuels sold orintroduced into commerce in the United States through 2022 for differentcategories of biofuels (see Table 2 below). There is an annuallyincreasing schedule for minimum aggregate use of total renewable biofuel(comprised of conventional biofuels and advanced biofuels), totaladvanced biofuel (comprised of cellulosic biofuels, biomass-baseddiesel, and other advanced biofuels), cellulosic biofuel and bio-baseddiesel. The RFS mandates are prorated down to “obligated parties”,including individual gasoline and diesel producers and/or importers,based on their annual production and/or imports.

Each year, obligated parties are required to meet their prorated shareof the RFS mandates by accumulating credits known as RINs, eitherthrough blending designated quantities of different categories ofbiofuels, or by purchasing from others the RINs of the required biofuelcategories.

The RIN system was created by the EPA to facilitate compliance with theRFS. Credits called RINs are used as a currency for credit trading andcompliance. RINs are generated by producers and importers of renewablebiofuels and assigned to the volumes of renewable fuels transferred intothe fuel pool. RINs are transferred with a fuel through the distributionsystem until they are separated from the fuel by parties who areentitled to make such separation (generally refiners, importers, orparties that blend renewable fuels into finished fuels). Afterseparation, RINs may be used for RFS compliance, held for futurecompliance, or traded. There is a centralized trading systemadministered by the U.S. EPA to manage the recording and transfer of allRINs.

According to certain embodiments of the invention, a RIN may becharacterized as numerical information. The RIN numbering system was inthe format KYYYYCCCCFFFFFBBBBBRRDSSSSSSSSEEEEEEEE where numbers are usedto designate a code representing whether the RIN is separated from orattached to a specific volume (K), the calendar year of production orimport (YYYY), Company ID (CCCC), Facility ID (FFFFF), Batch Number(BBBBB), a code for fuel equivalence value of the fuel (RR), a code forthe renewable fuel category (D), the start of the RIN block (SSSSSSSS)and the end of the RIN block (EEEEEEEE) Under current regulations, a RINcontains much of the foregoing information and other information in theform of data elements that are introduced into a web-based systemadministered by the EPA known as the EPA Moderated Transaction System,or “EMTS”. It should be appreciated, however, that the informationrequired for RIN generation and/or the format of the information maychange depending on prevailing regulations.

The D code of a RIN specifies the fuel type, feedstock and productionprocess requirements and thus in certain embodiments of the inventionthe D code may be used to characterize the type of RIN, as describedhereinafter. The D code of a RIN is assigned a value between 3 and 7under current regulations. The value assigned depends on the fuel type,feedstock and production process requirements as described in Table 1 to40 C.F.R. §80.1426. Examples of fuels assigned a D code of 3-7 undercurrent regulations are provided below. These examples are forillustration purposes only and are not to be considered limiting to theinvention.

TABLE 1 RIN D code examples D code Fuel Type Example 3 Cellulosicbiofuel Ethanol from cellulosic biomass from agricultural residues 4Biomass-based diesel Biodiesel and renewable diesel from soy bean oil 5Advanced biofuel Ethanol from sugarcane 6 Renewable fuel Ethanol fromcorn starch (conventional biofuel) 7 Cellulosic diesel Diesel fromcellulosic biomass from agricultural residues

As described previously, the RFS2 mandate volumes are set by fourseparate but nested category groups, namely renewable biofuel, advancedbiofuel, cellulosic biofuel and biomass-based diesel. The requirementsfor each of the nested category groups are provided in Table 2.

The nested category groups are differentiated by the D code of a RIN. Toqualify as a total advanced biofuel, the D code assigned to the fuel is3, 4, 5 or 7, while to qualify as cellulosic biofuel the D code assignedto the fuel is 3 or 7 (Table 2).

According to current regulations, each of the four nested categorygroups requires a performance threshold in terms of GHG reduction forthe fuel type. In order to qualify as a renewable biofuel, a fuel isrequired to meet a 20% life cycle GHG emission reduction (or be exemptfrom this requirement), while advanced biofuel and biomass-based dieselare required to meet a 50% life cycle GHG emission reduction andcellulosic biofuels are required meet a 60% life cycle GHG emissionreduction, relative to a gasoline baseline. As well, each nestedcategory group is subject to meeting certain feedstock criteria.

TABLE 2 Nested category groups under RFS2 Life cycle GHG thresholdNested reduction relative category to gasoline group Fuel type baselineRenewable Conventional biofuels (D code 6) 20% biofuel and advancedbiofuels (D code 3, 4, 5 or 7) Advanced Cellulosic biofuels (D code 3 or50% biofuel 7), biomass-based diesel (D code 4 or 7), and other advancedbiofuels (D code 5) Cellulosic Biofuel derived from cellulosic 60%biofuels material (D code 3) and bio-diesel derived cellulosic material(D code 7). Biomass-based Conventional biodiesel (D code 4) 50% dieselor cellulosic diesel (D code 7)

Thus, according to certain embodiments of the invention, a RIN creditcontaining information or a value corresponding to a reduction in lifecycle GHG emissions relative to a baseline is generated with theproduction of a volume of biogenic carbon-based fuel produced by theprocess. The information may correspond to a reduction in life cycle GHGemissions of at least 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 85%relative to a gasoline baseline. The invention may contribute wholly orin part to achieving reductions in the life cycle GHG emissions of abiogenic carbon-based fuel relative to a gasoline baseline.

The RIN associated with biogenic carbon-based fuel may be assigned a Dcode of 3, 4, 5 or 7, also referred to herein as a D3, D4, D5 and D7RIN, respectively. According to certain embodiments, the RIN associatedwith the biogenic carbon-based fuel may be assigned a D code of 3 or 5.Under current regulations, this corresponds to cellulosic biofuel andadvanced biofuel fuel types, which meet GHG emissions reductions of 60%and 50%, respectively, relative to a gasoline baseline.

According to some embodiments of the invention, the fuel credit ischaracterized as containing numerical information associated with theone or more products produced by the process of the invention for use asa transportation or heating fuel. Thus, a party may generate a fuelcredit comprising numerical information relating to one or more productsof the process representing at least one parameter selected from (i) thetype of transportation or heating fuel; (ii) the year in which theproduct was produced; (iii) a registration number associated with theproducer or importer; and (iv) serial number associated with a batch. Ina further embodiment, at least two parameters or at least threeparameters are selected from the foregoing list. The numericalinformation may also include one or more of the following parametersselected from: (i′) a number identifying that the numerical informationis assigned to a volume of the product, or separated; (ii′) aregistration number associated with the facility at which the productwas produced or imported; (iii′) a number representing a value relatedto an equivalence value of the product; (iv′) a number representing afirst-volume numerical information associated with a batch of theproduct; and (v′) a number representing a last-volume numericalinformation associated with a batch of the product.

The RIN or numerical information described herein or a portion thereofis provided to a government regulatory agency, including the EPA, inconnection with generating a RIN. In some embodiments of the invention,the numerical information is also provided to a purchaser of thebiogenic carbon-based fuel produced by the invention. The numericalinformation described herein or portions thereof may be storedelectronically in computer readable format.

The purchaser of the biogenic carbon-based fuel may separate the RIN. Asdescribed above, separation of a RIN from a volume of the biogeniccarbon-based fuel for use as a transportation or heating fuel, meanstermination of the assignment of the RIN to a volume of fuel. RINseparation is typically carried out by a fuel blender, importer or otherobligated party. According to pre-2010 regulations, when a RIN isseparated, the K code of the RIN is changed to 2.

Separation of RINs may be conducted in accordance with prevailing rulesand regulations, as currently provided in 40 C.F.R. §80.1129 and 40C.F.R. §80.1429. RINs generated in accordance with the invention may beseparated and subsequently traded.

It should be understood that the regulations under EISA, including RINrequirements and the criteria for categorization of a fuel under aparticular fuel category, such as life cycle GHG emission thresholds,are described herein in accordance with current regulations and can bereadily ascertained by those of skill in the art.

(b) Low Carbon Fuel Standard (LCFS)

The beneficial GHG emissions reductions achieved by the presentinvention can provide a means for meeting low carbon fuel standardsestablished by jurisdictions within the United States or othergovernment authorities. The credit, which includes a certificate, may beassociated with the biogenic carbon-based fuel, and represents or isproportional to the amount of life cycle GHG emissions reduced measuredrelative to a gasoline baseline. As set forth previously, the life cycleGHG emissions under low carbon fuel standards are often referred to ascarbon intensity or CI.

California's LCFS currently requires that all mixes of fuel that oilrefineries and distributors sell in the Californian market meet inaggregate the established targets for GHG emissions reductions.California's LCFS requires increasing annual reductions in the averagelife cycle emissions of most transportation fuels, up to a reduction ofat least 10% in the carbon intensity, which is a measure of the lifecycle GHG emissions, by 2020. Targets can be met by trading of creditsgenerated from the use of fuels with a lower GHG emission value thangasoline baseline. Similar legislation has been implemented by theprovince of British Columbia, Canada, the United Kingdom and by theEuropean Union.

According to some embodiments of the invention, LCFS fuel creditgeneration comprises generating information associated with the one ormore products produced by the process of the invention for use as atransportation or heating fuel. A party may generate informationrelating to at least one parameter selected from (i) a reporting period;(ii) a fuel pathway code; (iii) transaction information, including typeor date of a transaction; (iv) fuel production facility information; (v)fuel delivery methods; (vi) an amount of fuel used as a fossil fuelreplacement, such as gasoline or diesel; and (vii) credits or deficitsgenerated. In a further embodiment, information regarding at least twoparameters, at least three parameters or at least four parameters isgenerated from the foregoing list.

British Columbia, a province in Canada, approved a Renewable and LowCarbon Fuel Requirements Act, which requires parties who manufacture orimport the fuel into the province ensure that the renewable content andthe average carbon intensity of the fuel they supply meets levels set byregulations. Fuel suppliers are required to submit annual reportsregarding the renewable fuel content and carbon intensity of thetransportation fuels they supply. The province allows transfers of GHGcredits between fuel suppliers to provide flexibility in meeting therequirements of the regulation.

In the European Union, GHG emissions are regulated by a Fuel QualityDirective, 98/70/EC. In April 2009, Directive 2009/30/EC was adoptedwhich revises the Fuel Quality Directive 98/70/EC. The revisions includea new element of legislation under Article 7a that requires fuelsuppliers to reduce the GHG intensity of energy supplied for roadtransport (Low Carbon Fuel Standard). In particular, Article 7aspecifies that this reduction should amount to at least 6% by 31 Dec.2020, compared to the EU-average level of life cycle GHG emissions perunit of energy from fossil fuels in 2010. According to the Fuel QualityDirective, fuel/energy suppliers designated by member states of theEuropean Union are required to report to designated authorities on: (a)the total volume of each type of fuel/energy supplied, indicating wherethe fuel/energy was purchased and its origin; and (b) the life cycle GHGemissions per unit of energy. The European Union has also promoted theuse of biofuels through a Biofuel Directive (2003/30/EC), which mandatescountries across the EU to displace certain percentages oftransportation fuel with biofuels by target dates.

The United Kingdom has a Renewable Transport Fuel Obligation (RTFO) inwhich biofuel suppliers are required to report on the level of carbonsavings and sustainability of the biofuels they supplied in order toreceive Renewable Transport Fuel Certificates (RTFCs). Suppliers reporton both the net GHG savings and the sustainability of the biofuels theysupply according to the appropriate sustainability standards of thefeedstocks from which they are produced and any potential indirectimpacts of biofuel production, such as indirect land-use change orchanges to food and other commodity prices that are beyond the controlof individual suppliers. Suppliers that do not submit a report will notbe eligible for RTFCs.

Certificates can be claimed when renewable fuels are supplied and fuelduty is paid on them. At the end of the obligation period, thesecertificates may be redeemed to the RTFO Administrator to demonstratecompliance. Certificates can be traded and if obligated suppliers do nothave a sufficient amount of certificates at the end of an obligationperiod they may “buy-out” the balance of their obligation by paying abuy-out price.

The present invention has been described with regard to one or moreembodiments. However, it will be apparent to those of skill in the artthat a number of variations and modifications can be made withoutdeparting from the scope of the invention as defined in the claims.

EXAMPLES Example 1 Producing Biogenic Ethanol Using Fossil DerivedHydrogen and Biogenic Carbon Dioxide

In this example, biogenic carbon dioxide and fossil derived hydrogen arefed to a bioreactor and fermented to ethanol by Clostridium ljungdahliibacteria that carry out the following bioconversion:6H₂+2CO₂→CH₃CH₂OH+3H₂O.

The hydrogen for the foregoing reaction is produced by a hydrogenproduction process using fossil methane as the feedstock. Fossil carbondioxide produced from the hydrogen production that is otherwise ventedis introduced underground to reduce life cycle GHG emissions. Theprocess flow sheet is described below in relation to FIG. 1.

As shown in FIG. 1, corn is the feed to a dry milling process employingfermentation 10 to produce biogenic ethanol. The corn is first treatedby grinding and enzyme treatment in a slurry. The resultant slurry isthen fed to fermentation unit 10 and fermented with Saccharomycescerevisiae yeast to produce ethanol and a biogenic CO₂ stream 20, whichis purified. In this example, the CO₂ stream 20 is assumed to contain100 mole % CO₂ (Table 3). The biogenic CO₂ stream 20 is combined withfossil derived hydrogen stream 30 to produce a combined stream 40comprising biogenic CO₂ and fossil derived hydrogen.

A first step involved in producing the fossil derived hydrogen stream 30involves feeding fossil methane stream 45 to a steam methane reformer(SMR) unit 50. The amount of methane in the fossil methane feed stream45 to the SMR unit 50 is 92.9 mol % (Table 3). In the steam methanereformer unit 50, the methane is converted to carbon monoxide andhydrogen by the following reaction with water to produce an SMR outletstream 60 comprising carbon monoxide and hydrogen:CH₄+H₂O→CO+3H₂

The SMR outlet stream 60 from the steam methane reformer unit 50 thuscontains not only hydrogen from a fossil source, but also fossil carbonin the form of carbon monoxide. The fossil carbon monoxide in SMR outletstream 60 is subsequently reacted with water to produce fossil carbondioxide and additional hydrogen in a water gas shift (WGS) unit 70 asper the following reaction.CO+H₂O→CO₂+H₂The water gas shift unit 70 increases the yield of hydrogen from fossilmethane, while converting the fossil CO to fossil carbon dioxide. Inthis example, the water gas shift reaction in the water gas shift unit70 comprises both a high and a low temperature shift (not shown). Theoverall conversion of fossil methane to carbon dioxide and hydrogen isas follows:Overall: CH₄+2H₂O→CO₂+4H₂.

An outlet stream 80 from the water gas shift unit 70 is then treated toremove carbon dioxide in carbon dioxide recovery unit 85 to produce acarbon dioxide-depleted stream 86 and a fossil carbon dioxide stream 87that is eventually introduced underground for enhanced oil recovery(EOR) 100 as described below. The carbon dioxide-depleted stream 86 isfed to a pressure swing adsorption (PSA) unit 90. The pressure swingadsorption unit 90 separates the hydrogen that originates from fossilfuel from any remaining fossil carbon dioxide and other non-hydrogencomponents such as methane and carbon monoxide. This produces the stream30 that is enriched in fossil derived hydrogen and a purge stream 91containing fossil carbon dioxide. In this example, the stream 30comprises 99.9 mol % hydrogen (Table 3). Although carbon dioxiderecovery from stream 80 is shown, carbon dioxide can be recovered fromother stages of the hydrogen production process. (See FIG. 5, forexample locations A, B or C). In this example, a purge stream 91remaining after carbon dioxide removal is introduced to the furnace ofthe steam methane reformer unit 50 to provide heat energy to the unit.

The recovered fossil carbon dioxide is introduced to a pipeline (notshown) for transporting carbon dioxide. Carbon dioxide is withdrawn fromthe pipeline (not shown), typically by another party through acontractual arrangement, and then introduced underground to recover oilas part of an enhanced oil recovery operation (EOR) 100. By introducingthe fossil carbon dioxide underground, the life cycle GHG emissionsassociated with the biogenic ethanol produced by the process can besignificantly reduced.

The fossil derived hydrogen stream 30 comprising 99.9% mol % hydrogen iscombined with the biogenic CO₂ stream 20 as described previously to forma stream 40 and fed to a fermentation bioreactor 110. In anotherembodiment (not illustrated), the fossil derived hydrogen stream 30 andthe biogenic CO2 stream 20 are fed separately to the fermentationbioreactor 110. In the fermentation bioreactor 110 the biogenic carbondioxide and fossil derived hydrogen are fermented to ethanol byClostridium ljungdahlii bacteria. A fermented stream 120 is withdrawnfrom the fermentation bioreactor 110 and fed to a distillation unit 130to produce concentrated biogenic ethanol 115, which is furtherconcentrated beyond its azeotropic breaking point by molecular sieves(not shown).

Material balances for the fossil methane feed 45, the fossil derivedhydrogen stream 30 and biogenic CO₂ stream 20 are provided in Table 3below. These values were used to calculate the life cycle GHG emissionsof the biogenic ethanol relative to a gasoline baseline, which isdiscussed below in Example 2.

Table 3 also shows the calculated increase in theoretical yield ofbiogenic ethanol from the process described in FIG. 1 relative to themethane feed, referred to hereinafter as the “biogenic ethanolefficiency” or “efficiency”. The efficiency achieved by theabove-described process relative to the fossil methane feed is 58%(mmBTU of ethanol/mmBTU of fossil methane feed). The calculations assumethe yield in gas fermentation is 81%. The assumed recoverable CO₂ fromthe ethanol plant is 5.3 lbs of CO₂ for each gallon of ethanol produced.These assumptions were also made in calculating the life cycle GHGemission reductions for this example and in the subsequent examples.

TABLE 3 Material balance, mass ratio, biogenic ethanol efficiency andenergy inputs and outputs for ethanol produced using a hydrogen enrichedstream and fossil CO₂ introduction underground Fossil PSA BiogenicNon-biogenic Biogenic methane outlet H₂ CO₂ ethanol ethanol feed streamstream produced produced Stream No. (FIG. 1) 45 30 20 115 115 Materialbalance H₂ mol% 2.9 99.9 CO mol% CO₂ mol% 1.9 100.0 CH₄ mol% 92.2 0.1 N₂mol% 2.4 H₂O mol% 0.5 Ethanol mol% 0 100.0 TOTAL mol% 100.0 100.0 100.00.0 100.0 Mass ratios lb/mmBTU of fossil 46.5 16.2 117.6 — 49.8 methanefeed Biogenic ethanol efficiency Gallons 7.6 ethanol/mmBTU of fossilmethane feed Energy input/output mmBTU/mmBTU of 100% 83% 0% 58% fossilmethane feed

Example 2 Comparison of GHG Emission Calculations for a Process with aWater Gas Shift and Introduction of Fossil CO₂ Underground Versus aProcess without Such Steps

The life cycle GHG emissions of the process described in Example 1 andFIG. 1 relative to a gasoline baseline were calculated and aresummarized in Table 4 below. The calculations show that by using thehydrogen enriched stream 30 produced by the hydrogen production processoutlined in Example 1 in the above-described ethanol fermentation, andby introducing fossil carbon dioxide stream 87 from the hydrogenproduction underground to extract oil, the life cycle GHG emissions forthe total ethanol produced can be reduced by 24% relative to a gasolinebaseline.

TABLE 4 Summary of life cycle GHG emissions for ethanol produced using ahydrogen enriched stream and fossil CO2 introduction underground UsageEmission Emissions BTU/gal intensity from fuel ethanol g CO₂eq/mmBTU gCO₂eq/mmBTU Units produced fuel used ethanol produced Natural gas usage132,325 68,575 117,847 (SMR feed) Electricity usage 9,261 219,812 26,438CO₂ recovered from (69,535) SMR production (credit) Tailpipe emissions 0TOTAL 141,586 74,749 Life cycle GHG emission reduction relative to the24% gasoline baseline* *98,204 g CO₂eq/mmBTU ethanol produced obtainedfrom 2010 Final Rule-Federal Register /Vol. 75, No. 58/Friday, Mar. 26,2010/Rules and Regulations

As noted above, the ethanol in this example contains only biogeniccarbon, and therefore, when the fuel is burned in an internal combustionengine, no fossil carbon is emitted to the atmosphere. Consequently, ascan be seen in Table 4 above, these emissions need not be accounted forin the life cycle emission calculations. Moreover, GHG emissionreductions result by introducing fossil carbon dioxide from hydrogenproduction underground. The fossil carbon dioxide recovered from SMRproduction and introduced underground results in a credit of 69,535 gCO₂eq/mmBTU ethanol produced.

Adding up the emission debits and credits gave a total life cycleemission value of 74,749 g CO₂eq/mmBTU ethanol produced, whichrepresents the above-noted 24% reduction relative to the gasolinebaseline of 98,204 g CO₂eq/mmBTU ethanol produced.

For comparison, similar calculations were performed for a processotherwise identical to FIG. 1, but that omits the water gas shift 70,fossil carbon dioxide removal 85, the pressure swing adsorption unit 90and the introduction of fossil carbon dioxide from the processunderground to extract oil in an enhanced oil recovery (EOR) operation100. In such comparative process, a syngas stream comprising fossilcarbon and hydrogen instead of a stream enriched in hydrogen is fed tothe fermentation bioreactor. There is no credit for CO₂ recovered fromSMR production and introduced underground. The calculations describedbelow show that the ethanol produced by this process does not have afavourable GHG emission balance and in fact results in an increase inthe life cycle GHG emissions relative to a gasoline baseline.

The flowsheet for this latter comparative process is depicted in FIG. 2.Like reference numbers among FIGS. 1 and 2 represent identical orsimilar process steps or unit operations.

Similar to FIG. 1, in the comparative process depicted in FIG. 2, cornis the feed to a process employing fermentation to produce ethanol. Thecorn is treated by grinding and enzyme treatment in a slurry (notshown). The slurry is then fermented in fermentation 10 withSaccharomyces cerevisiae yeast to produce ethanol 12 and biogenic CO₂stream 20.

However, unlike the process depicted in FIG. 1, the biogenic CO₂ stream20 is combined with a fossil syngas stream 55. The syngas stream 55results from the conversion of fossil methane 45 to fossil carbonmonoxide and fossil hydrogen by a steam methane reforming unit 50 inwhich the following reaction is carried out:CH₄+H₂O→CO+3H₂

Because no water gas shift reaction occurs and no CO₂ is introducedunderground, the stream 55 blended with stream 20 contains not onlyhydrogen from a fossil source, but also fossil carbon in the form ofcarbon monoxide. The fossil syngas stream 55 composition is provided inTable 5 below and contains 49.1 mol % fossil hydrogen and 9.7 mol %carbon monoxide (wet basis).

The stream 55 comprising fossil syngas is subsequently combined withbiogenic CO₂ stream 20 to produce a combined stream 40 comprising fossilcarbon monoxide, hydrogen and carbon dioxide from fossil fuel andbiogenic carbon dioxide.

In the fermentation bioreactor 110 illustrated in FIG. 2 the biogeniccarbon dioxide from stream 20 and the syngas from stream 55 (comprisingcarbon monoxide, carbon dioxide and hydrogen from fossil fuel) arefermented to ethanol by Clostridium ljungdahlii bacteria. The followingreactions occur to produce ethanol:6CO+3H₂O→CH₃CH₂OH+4CO₂6H₂+2CO₂→CH₃CH₂OH+3H₂O

Since the carbon monoxide and carbon dioxide in the fossil syngas stream55 are fossil derived, for the comparative process illustrated in FIG.2, the first reaction will produce ethanol and carbon dioxide comprisingfossil carbon. The fossil carbon dioxide that is produced by the firstreaction will go on to produce ethanol which contains fossil carbon. Asa result, a significant portion of the ethanol in stream 115 willcontain fossil carbon and thus will need to be accounted for in the formof tailpipe emissions upon combusting the ethanol in vehicles.

Similar to FIG. 1, FIG. 2 illustrates a fermented solution stream 120that is withdrawn from the fermentation bioreactor 110 and fed todistillation unit 130 to produce the concentrated ethanol in stream 115,which is further concentrated beyond its azeotropic breaking point bymolecular sieves (not shown).

Material balance and other assumptions made for the life cycle GHGemission calculations, as well as ethanol efficiency calculations, forthe process of FIG. 2 are described in Table 5 below.

TABLE 5 Material balance, mass ratio, biogenic ethanol efficiency andenergy inputs and outputs for ethanol produced using fossil syngas fromSMR and without fossil CO₂ introduction underground Fossil FossilBiogenic Non-biogenic Biogenic methane syngas CO₂ ethanol ethanol feedstream stream produced produced Stream No. (FIG. 2) 45 55 20 115 115 H₂mol% 2.9 49.1 CO mol% 9.7 CO₂ mol% 1.9 5.4 100.0 CH₄ mol% 92.2 4.1 N₂mol% 2.4 0.0 H₂O mol% 0.5 31.7 Ethanol mol% 100.0 100.0 TOTAL mol% 100.0100.0 100.0 100.0 100.0 Mass ratios lb/mmBTU of 46.5 187 29.9 42.4 12.7fossil methane feed Biogenic ethanol efficiency Gallons 6.4 1.9ethanol/mmBTU of fossil methane feed Energy input/output mmBTU/mmBTU100% 117% 50% 15% of fossil methane feed

The life cycle GHG emissions of the process described FIG. 2 relative toa gasoline baseline are summarized in Table 6 below.

TABLE 6 Summary of life cycle GHG emissions for ethanol produced usingsyngas from SMR and without fossil CO₂ introduction underground UsageEmission intensity Emissions from fuel BTU/gal ethanol g CO₂eq/mm BTUfuel g CO₂eq/mm BTU Units produced used ethanol produced Fossil methane119,639 68,575 106,549 usage (SMR feed) Electricity Usage 9,261 219,81226,438 Tailpipe emissions 71,247 from fossil carbon combustion TOTAL128,900 204,234 Life cycle GHG emission reduction relative to thegasoline baseline* −108% *98,204 g CO₂eq/mmBTU ethanol produced obtainedfrom 2010 Final Rule-Federal Register/Vol. 75, No. 58/Friday, Mar. 26,2010/Rules and Regulations

The above calculations show that by using a syngas stream from a steammethane reforming process in an ethanol fermentation, without a watergas shift, or carbon dioxide purification and without introducing anyfossil carbon dioxide underground, the life cycle GHG emissions areactually increased by 108% relative to a gasoline baseline (depicted as−108% relative to a gasoline baseline in Table 6). Such increases in GHGemissions result in part from the need to account for tailpipe emissionsfrom fossil carbon combustion, which are 71,247 g CO₂eq/mmBTU ethanolproduced, and also the absence of a credit associated with recoveringCO₂ from SMR production and introducing it underground.

Therefore, by implementing an embodiment of the invention with the stepsof CO₂ disposition, and using a hydrogen enriched stream from fossilsources, significant GHG emission reductions relative to a gasolinebaseline can be realized in comparison to a process without implementingsuch steps.

A further advantage that becomes evident from comparing the ethanolefficiency results in Table 3 with Table 5 is that by carrying out theembodiment of the invention depicted in FIG. 1, the efficiency ofproducing biogenic ethanol is greatly increased relative to thecomparative process of FIG. 2. As noted, by using the hydrogen enrichedstream to produce the biogenic ethanol and by introducing the fossilcarbon dioxide underground, the amount of biogenic ethanol energyproduced relative to the methane feed energy is 58%. In contrast, thecomparative process depicted in FIG. 2 only resulted in an efficiency of15% biogenic ethanol. This is because in this latter process, themajority of the ethanol produced is non-biogenic (23% biogenic and 77%fossil). Not only does this require accounting for tailpipe emissions,which increases GHG emissions, but also the majority of the fuel productmay not be considered renewable in some jurisdictions, which in turn mayreduce its environmental and commercial value.

Example 3 GHG Emission Calculations of an Embodiment EmployingDisplacement

In this example, life cycle GHG emissions were calculated for a processin which biogenic carbon dioxide is sourced from a fermentationconducted as part of a cellulosic ethanol conversion process. Thebiogenic carbon dioxide collected is combined with fossil derivedhydrogen and fermented to produce biogenic ethanol as describedpreviously in Example 1.

In the cellulosic ethanol conversion process, lignin is combusted toproduce steam and electricity, for the cellulosic ethanol plant and theexcess energy is sold to the electricity grid. The electricity derivedfrom non-fossil organic material displaces the production or use offossil derived electricity from a coal burning power plant.

The process flow diagram is shown in FIG. 3. Like reference numbersamong FIGS. 1, 2 and 3 represent identical or similar process steps orunit operations.

As shown in FIG. 3, biomass is subjected to a pretreatment 2 to make thebiomass more amenable to enzymatic hydrolysis. Pretreatment of thebiomass typically involves the addition of pretreatment chemical andheat to hydrolyze at least a portion of the hemicellulose component ofthe biomass. The pretreated biomass is then hydrolyzed with cellulaseenzymes in hydrolysis unit 4 to produce glucose. The hydrolyzedmaterial, comprising glucose and other hexose and pentose sugars, aswell as unhydrolyzed, insoluble material comprising lignin, is fed to asolids-liquid-separation unit 5. The solids-liquid-separation (SLS) unit5 produces a stream 6 comprising lignin and an aqueous stream 8comprising sugar. The stream 6 comprising lignin is combusted in lignincombustion unit 7 to produce steam and electricity for the plant and theexcess electricity is sent to the grid for external use, therebydisplacing fossil derived electricity. The aqueous stream 8 comprisingsugar is fed to a fermentation unit 10 to produce biogenic ethanol andbiogenic carbon dioxide is collected to produce a biogenic CO₂ stream20.

The biogenic CO₂ stream 20 is combined with a fossil derived hydrogenstream 30. The fossil derived hydrogen stream 30 is produced from fossilmethane according to the process described in Example 1, except fossilcarbon dioxide is not introduced underground in enhanced oil recovery toextract oil. A combined stream 40 comprising fossil derived hydrogenfrom stream 30 and biogenic carbon dioxide from stream 20 is fermentedto biogenic ethanol in fermentation bioreactor 110. A fermented solutionstream 120 is sent to distillation unit 130 to concentrate the biogenicethanol.

The life cycle GHG emissions relative to a gasoline baseline for theforegoing process with displacement of fossil electricity withelectricity derived (referred to as “export”) from lignin combustion 7were calculated. For comparison, the same GHG analysis was alsoperformed on a process without such displacement (referred to as “noexport”), but that is otherwise similar to the process outlined in FIG.3. The avoidance of power export can typically be achieved by investingless in energy recovery equipment. The mass balance assumptions for thecomposition of the fossil methane to the SMR 50, the composition of thehydrogen enriched stream 30 and the biogenic CO₂ stream 20, as well asother assumptions described in Table 3 above, are the same as in Example1.

The calculations were performed for two processes in which either switchgrass or corn stover respectively were used as the feedstock. Theresults of the analysis with and without displacement by export ofelectricity for switch grass are presented in Table 7 and similarcalculations for corn stover are presented in Table 8 below.

TABLE 7 Summary of life cycle GHG emissions for ethanol produced using ahydrogen enriched stream and fossil derived electricity displacementfrom lignin combustion with switch grass Emissions from Emissions fromfuel - export Emission fuel - no export g Usage intensity gCO₂eq/aggregate BTU/gal g CO₂eq/aggregate mmBTU ethanol CO₂eq/mmB mmBTUethanol ethanol Units produced TU fuel used produced producedAgriculture/Land Use 298 298 Fuel Production (cellulosic ethanol and gasfermentation) Natural Gas 33,628 68,575 29,949 29,949 Electricity 2,356219,812 6,726 6,726 Other 2,968 2,968 Fuel and Feedstock 2,238 2,238Transport Tailpipe Emissions 746 746 Electricity export (3,863) 219,812— (11,138) credit TOTAL 56,797 45,659 Life cycle GHG emission reduction42% 54% relative to the gasoline baseline** *98,204 g CO₂eq/mmBTUethanol produced obtained from 2010 Final Rule-Federal Register/Vol. 75,No. 58/Friday, Mar. 26, 2010/Rules and Regulations

TABLE 8 Summary of life cycle GHG emissions for ethanol produced using ahydrogen enriched stream andwithout electricity displacement with cornstover Emissions Emissions from fuel - from fuel - no export export g gEmission CO₂eq/ CO₂eq/ Usage intensity aggregate aggregate BTU/gal gCO₂eq/ mmBTU mmBTU ethanol mmBTU ethanol ethanol Units produced fuelused produced produced Agriculture/Land 298 298 Use Fuel Production(cellulosic ethanol and gas fermentation) Natural Gas 33,628 68,57529,949 29,949 Electricity 2,356 219,812 6,726 6,726 Other 2,968 2,968Fuel and 1,492 1,492 Feedstock Transport Tailpipe 746 746 EmissionsElectricity export (3,863) 219,812 — (11,138) credit TOTAL 42,178 31,040Life cycle GHG emission reduction 57% 68% relative to the gasolinebaseline* *98,204 g CO₂eq/mmBTU ethanol produced obtained from 2010Final Rule-Federal Register /Vol. 75, No. 58/Friday, Mar. 26, 2010/Rulesand Regulations

As shown in Table 7 above, the life cycle GHG emission reductionrelative to a gasoline baseline for the fuel production process forswitch grass which implements the electricity displacement describedabove is 54% relative to the gasoline baseline, but only 42% withoutsuch displacement. A contributor to the favorable GHG emission reductionwith the displacement is the electricity export credit of 11,138 gCO₂eq/mmBTU ethanol produced. Likewise, as shown in Table 8 above, usingcorn stover as the feedstock, the life cycle GHG emission reductions are68% relative to the baseline with displacement of fossil electricity,while only 57% without the displacement.

The above reductions in life cycle GHG emissions due to the displacementcan lead to advantaged fuel credit generation. As noted previously, theGHG emission reduction threshold for generation of a Cellulosic Biofuelis 60%, while the threshold for generation of an Advanced Biofuel is50%. (See Table 2 above). By implementing the displacement described inthis example using corn stover as a feedstock, since the GHG emissionreduction is 68% relative to the baseline, both thresholds are exceeded.By contrast, without such displacement, since only a 57% reductionrelative to the baseline is reached, only the Advanced Biofuel thresholdis exceeded (Table 7). Moreover, by practicing the process withdisplacement using switch grass as the feedstock, since the GHG emissionreduction relative to the baseline is 54%, the Advanced Biofuel GHGthreshold can be exceeded. However, for the same process without suchdisplacement, the GHG emission reduction is only 42% and thus neitherthe Advanced Biofuel nor the Cellulosic Biofuel threshold is reached(Table 8).

In addition, embodiments of the invention also enable LCFS fuel creditgeneration. Under LCFS legislation appreciated by those skilled in theart, the above-noted increased reductions in life cycle GHG emissionswith displacement can enable an increase in the number of fuel creditsgenerated.

Example 4 Producing Biogenic Gasoline Using Fossil Derived Hydrogen andBiogenic Carbon Dioxide

In this example, biogenic gasoline is produced from fossil derivedhydrogen and biogenic carbon dioxide. In the process detailed below,carbon dioxide and fossil derived hydrogen are fed to a steam methanereformer. In the reformer, the biogenic carbon dioxide and fossilderived hydrogen react to produce a syngas stream comprising carbonmonoxide, hydrogen and carbon dioxide via a reverse water gas shiftreaction. The resultant syngas, containing biogenic carbon and fossilderived hydrogen, is then converted to gasoline via methanol anddimethylether intermediates as described below. Advantageously, thegasoline qualifies as biogenic since the carbon atoms in the moleculeoriginate from biogenic carbon dioxide or qualify as renewable.

A process study design was conducted for the foregoing process bygenerating modeling data. The process flow sheet and data are describedin relation to FIG. 4.

The study design was based on the availability of 1,000 metric tons ofbiogenic carbon dioxide per day (t/d), indicated as biogenic CO₂ stream20. The biogenic CO₂ stream is collected from a fermentation ofnon-fossil organic material to produce ethanol, from gasification ofbiomass or from anaerobic digestion of landfill waste (not shown).Biogenic CO₂ stream 20 is treated to remove impurities such as sulfurcompounds as they are poisonous to the reforming catalyst (not shown).The biogenic CO₂ stream is then compressed in CO₂ compression unit 25 toproduce a compressed biogenic CO₂ stream 28. The temperature of thecompressed biogenic CO₂ stream 28 is 200° F. (93° C.), the pressure is430 psig and the total flow is 2098.8 lbmol/hr. The compressed biogenicCO₂ stream 28 is then combined with a fossil derived hydrogen stream 30and a steam stream 32. The fossil derived hydrogen stream 30 has atemperature of 108° F. (42° C.), a pressure of 430 psig and a total flowof 7491 lbmol/hr. The steam stream 32 is at a temperature of 750° F.(399° C.), a pressure of 450 psig and a total flow of 2214.6 lbmol/hr.

The fossil derived hydrogen stream 30 is produced by steam methanereforming and a water gas shift reaction (not shown). The overallreaction for production of hydrogen isOverall: CH₄+2H₂O→CO₂+4H₂.

The fossil carbon dioxide produced from the above reaction is introducedunderground to extract oil in an enhanced oil recovery operation (notshown).

The combined stream 40 comprising the hydrogen, biogenic carbon dioxideand steam is fed to a pre-heater 42 at a temperature of 212° F. (100°C.). The temperature of the outlet stream 44 from the pre-heater is1000° F. (538° C.). The heated outlet stream 44 that is fed to areformer 46 comprises the following components on a mole % basis: H₂O(0.1887), N₂ (0.0026), CO₂ (0.1771), H₂ (0.6299), CO (0.0000) and CH₄(0.0018). The steam reformer 46 operating conditions were adjusted tomatch the requirements for syngas fed to the gasoline productionprocess. The steam reforming conditions used for the example were:

TABLE 9 Steam reforming conditions Catalyst tube outlet temperature1600° F. (871° C.) Catalyst tube outlet pressure 400 psig Steam reformerfeed pre-heat 1000° F. (538° C.) Radiant section Bridgewall 1800° F.(982° C.) Temperature (BWT) Steam:carbon molar ratio 1.05

The steam reformer 46 produces an outlet stream 48 comprising thefollowing components on a mole % basis H₂O (0.3411), N₂ (0.0027), CO₂(0.0616), H₂ (0.4698), CO (0.1017) and CH₄ (0.0232).

After the stream reformer 46, the outlet stream 48, which is at atemperature of 1600° F. (871° C.) is sent to a waste heat boiler (WHB)unit 52, which recovers energy from the outlet stream 48. An outletstream 54 from the WHB unit 52, at a temperature of 1100° F. (593° C.)is fed to a heat recovery unit 56. An outlet stream 58 from the heatrecovery unit 56 at a temperature of 338° F. (170° C.) is fed to coolers62, which produce a steam condensate stream 64 and a cooled syngasstream 66. The conversion of feed carbon from the biogenic carbondioxide to carbon monoxide in syngas was determined to be 54.6%.

The syngas stream 66 can be used in various ways (not illustrated inFIG. 4). For example, in order to produce biogenic gasoline, the syngasstream 66 produced by the above reforming process is converted tomethanol and the methanol is then converted to dimethylether by adehydration reaction. Subsequently, an equilibrium mixture of methanol,dimethylether and water is converted to short-chain olefins. In afurther reaction step, the short-chain olefins are reacted to formhigher olefins, including n/iso-paraffins, aromatics and napththenes,which are further treated to make the biogenic gasoline.

The foregoing process may employ heat integration. The steam reformer 46to produce syngas from biogenic carbon dioxide and hydrogen and thesteam methane reforming and/or a water gas shift to produce the hydrogen30 from fossil methane often generate excess heat. The heat generatedfrom any one or a combination of these reforming and water gas shiftoperations can be used to provide energy in other unit operations. Forinstance, the heat can be used to supply energy for convertingnon-fossil organic material to ethanol from which the biogenic CO₂ feed20 is produced as a byproduct. For example, such heat can be utilized ina dryer, thermal oxidizer, distillation and/or evaporation in an ethanolproduction process using corn as a feedstock. Alternatively, the heatcan be used in a production process to make ethanol from biomass orbiomass derived material. This includes supplying heat to similaroperations as a corn ethanol process or for pretreatment processes thatare utilized to make the biomass or biomass derived material moreaccessible to cellulase enzymes for cellulose hydrolysis. Heat from thereforming can also be used to supply energy for the gasoline productionprocess in which syngas is converted to biogenic gasoline via themethanol and dimethylether intermediates as described above. Further,the heat from the steam reformer 46 or the reformer or water-gas shiftunit (not shown) to produce the fossil derived hydrogen 30 can be usedto produce electricity for export to the grid. Such energy savings cancontribute to reducing the life cycle GHG emissions of the biogenicgasoline relative to a gasoline baseline and can enable the generationof a valuable biofuel credit in relation to the biogenic gasolineproduced or sold.

It should be understood that the foregoing examples describing theproduction of biogenic ethanol and gasoline are for illustrativepurposes only and should not be construed to limit the current inventionin any manner.

The invention claimed is:
 1. A process for using biogenic carbon dioxidederived from non-fossil organic material for fuel production comprising:(i) providing biogenic carbon dioxide that is sourced from a productionprocess comprising a step of fermentation; (ii) providing a streamenriched in hydrogen that is sourced from a hydrogen production processcomprising the steps of: (a) converting fossil methane to carbonmonoxide and hydrogen by reforming; (b) converting at least a portion ofthe carbon monoxide by a water-gas shift reaction to carbon dioxide,thereby producing a stream comprising carbon dioxide and hydrogen, and(c) separating at least a portion of the hydrogen from the stream ofstep (b) from non-hydrogen components to produce the stream enriched inhydrogen, which stream contains a molar ratio of hydrogen to both fossilcarbon monoxide and carbon dioxide of greater than 4:1; (iii) convertingthe biogenic carbon dioxide from step (i) and hydrogen produced in step(ii)(c) to a biogenic carbon-based fuel or fuel intermediate; and (iv)carrying out or arranging for one or more parties to carry out at leastone step that contributes to a reduction in the life cycle GHG emissionsof a fuel or a fuel made from a fuel intermediate produced by theprocess, wherein the life cycle GHG emissions of the fuel are at least20% lower than a gasoline baseline as determined b EPA methodology, saidat least one step selected from: (a) introducing at least a portion offossil carbon dioxide recovered from one or more streams comprisingfossil carbon dioxide generated during said hydrogen production processinto an apparatus for transporting carbon dioxide, withdrawing carbondioxide from said apparatus and introducing the withdrawn carbon dioxideunderground, and (b) using at least a portion of a product produced inthe production process of step (i) selected from a chemical and energyproduct to displace the use or production of a correspondingfossil-based product.
 2. The process of claim 1, wherein the biogeniccarbon-based fuel or fuel intermediate of step (iii) is an alcohol. 3.The process of claim 2, wherein the alcohol is ethanol or methanol. 4.The process of claim 1, wherein the biogenic carbon-based fuel or fuelintermediate of step (iii) is a liquid or gaseous hydrocarbon at 20° C.5. The process of claim 4, wherein the hydrocarbon is selected frommethane and gasoline.
 6. The process of claim 4, wherein the hydrocarbonis a liquid hydrocarbon produced by a Fischer Tropsch reaction.
 7. Theprocess of claim 1, wherein the converting of step (iii) comprises afermentation.
 8. The process of claim 7, wherein an alcohol is producedby the fermentation.
 9. The process of claim 8, wherein the alcohol isethanol.
 10. The process of claim 1, wherein the production process ofstep (i) produces at least one energy product that is steam,electricity, methane or lignin.
 11. The process of claim 1, wherein theproduction process of step (i) produces at least one of an alcohol andan organic acid.
 12. The process of claim 1, wherein the productionprocess of step (i) produces ethanol.
 13. The process of claim 12,wherein at least a portion of the biogenic carbon dioxide provided instep (i) is sourced from (a) a fermentation to produce the ethanol, (b)an anaerobic digestion of a process stream resulting after a step ofrecovering the ethanol, or (c) a combination thereof.
 14. The process ofclaim 13, wherein the production process of step (i) further comprisesthe production of lignin.
 15. The process of claim 1, wherein a fuel orfuel intermediate is produced in the production process of step (i) thatis the same type as the biogenic carbon-based fuel or fuel intermediateproduced in step (iii).
 16. The process of claim 1, wherein theproduction process of step (i) is an ethanol production processcomprising a step of producing biogenic ethanol from a fermentation andthe biogenic carbon dioxide is generated during the ethanol productionprocess and collected, and step (iii) comprises introducing biogeniccarbon dioxide from step (i) and hydrogen from step (ii) together orseparately to a fermentation reactor and forming additional biogenicethanol by converting the biogenic carbon dioxide and hydrogen in thereactor to biogenic ethanol by fermentation with a microorganism. 17.The process of claim 16, wherein the biogenic carbon dioxide andhydrogen are introduced together or separately with a fermentationbroth.
 18. The process of claim 1, further comprising generating orcausing the generation of a biofuel credit.
 19. The process of claim 18,wherein the biofuel credit is a RIN or an LCFS credit.
 20. The processof claim 1, further comprising exporting the energy product to displacethe use or production of the corresponding fossil-based product outsidethe production process of step (i).